A Step-by-Step Guide to Applying for a U.S. Patent

Last updated 4 months ago. Our resources are updated regularly but please keep in mind that links, programs, policies, and contact information do change.

A United States patent doesn’t give you the right to make or sell your invention. Instead, it grants something potentially more valuable: the power to stop others from making, using, selling, or importing your invention for up to 20 years.

This right serves as the inventor’s reward for teaching the world how their innovation works. It’s a bargain rooted in the Constitution itself—share your knowledge with society, and the government will protect your commercial advantage for a limited time.

The journey from idea to issued patent involves navigating a formal, complex legal process managed by the United States Patent and Trademark Office (USPTO).

This guide walks through each step, from determining whether your idea qualifies for patent protection to maintaining your rights after the patent is granted.

Is Your Invention Patentable?

Before investing time and money in the application process, you must determine whether your invention meets the fundamental legal requirements. Many promising ideas fail at this stage because they don’t clear three essential hurdles established by patent law.

The Three Pillars of Patentability

To earn a patent, an invention must be useful, novel, and non-obvious. These aren’t suggestions—they’re strict legal standards that a USPTO patent examiner will apply to every application.

Pillar One: Utility

The invention must have a useful purpose. The USPTO doesn’t grant patents for purely theoretical ideas, abstract concepts, laws of nature, or inventions that are inoperable, illegal, or against public policy.

The legal standard requires “specific, substantial, and credible” utility. A person of ordinary skill in the art—a hypothetical expert in the invention’s technical field—must immediately understand why the invention is useful based on its described characteristics.

A new type of hammer clearly has utility because it drives nails. A machine claiming perpetual motion would be rejected for lacking utility because it defies physics. A new chemical compound with no known function would fail the utility test, but if the inventor demonstrates the compound treats a specific disease, it passes.

Pillar Two: Novelty

The invention must be genuinely new. An invention isn’t novel if it was already known to the public before the effective filing date of the patent application. This existing public knowledge is called “prior art.”

Prior art includes anything publicly available: U.S. and foreign patents, published patent applications, websites, technical journals, books, conference presentations, or products that were on sale or in public use.

The novelty test involves a strict, one-to-one comparison. If a single piece of prior art discloses every element of the invention as described in a patent claim, that claim is “anticipated” by the prior art and will be rejected.

If you invent a new can opener and later discover an identical can opener was described in an Italian magazine six months before you filed, your invention isn’t novel and can’t be patented.

The One-Year Grace Period

U.S. inventors get one crucial advantage: a one-year statutory grace period. If you publicly disclose your own invention—by selling it, demonstrating it at a trade show, or publishing about it—you have exactly one year from that first disclosure to file a U.S. patent application.

Miss that deadline, and your own public disclosure becomes prior art that can sink your application. Most foreign countries don’t offer this grace period, so any public disclosure before filing can immediately forfeit patent rights in those countries.

Pillar Three: Non-Obviousness

Non-obviousness presents the highest hurdle. Even if an invention is technically new, it can’t be patented if the differences between it and existing prior art would have been obvious to a person of ordinary skill in the art when the invention was made.

This requirement ensures patents are only granted for true inventive leaps, not predictable modifications or combinations of existing technologies.

Unlike the novelty test, which looks for a single prior art reference showing the entire invention, the non-obviousness test allows examiners to combine multiple prior art references.

Imagine prior art shows a wooden chair, and a furniture journal teaches that plastic is a suitable substitute for wood in furniture. A patent application for a plastic version of that chair would likely be rejected as obvious because a skilled furniture maker would find the substitution obvious.

Overcoming Obviousness Rejections

You can argue that prior art “teaches away” from your invention, meaning it suggests the combination wouldn’t work or would be undesirable. You can also present “secondary considerations of non-obviousness”—evidence that your invention achieved commercial success, solved a long-felt industry problem, was praised by experts, or was copied by competitors.

While novelty is relatively straightforward to assess, non-obviousness is subjective and where most patent applications face their biggest challenge. You might easily confirm your exact invention doesn’t exist (it’s novel), only to have the application rejected because an examiner found it an obvious combination of things that did exist.

Choosing the Right Type of Intellectual Property

Make sure a patent is the correct form of intellectual property protection for your creation. The USPTO issues patents for inventions but doesn’t protect other forms of creativity.

Copyright protects original works of authorship like books, songs, and paintings. Copyright is administered by the U.S. Copyright Office, part of the Library of Congress.

Trademark protects words, names, symbols, sounds, or colors that distinguish goods and services. This includes brand names and logos. Trademarks are handled by the USPTO through a separate process from patents.

The USPTO provides a helpful IP Identifier tool to help creators determine which form of protection fits their work.

Three Types of U.S. Patents

Once you confirm a patent is the right protection, choose the correct type. The USPTO grants three distinct types, each designed to protect different kinds of inventions.

Utility Patents are the most common type and protect how an invention works or is used. They cover any new and useful process, machine, article of manufacture, or composition of matter, plus any new and useful improvement. This broad category includes computer software, medical devices, chemical compounds, and new manufacturing methods.

Design Patents protect how an invention looks. They cover new, original, and ornamental designs for articles of manufacture. A design patent protects aesthetic appearance, not functional aspects. Famous examples include the original Coca-Cola bottle shape or a smartphone app’s graphical user interface.

Plant Patents protect new and distinct varieties of plants that have been asexually reproduced (not from seed). This includes plants created through grafting or cutting, such as new hybrids or mutants. Plant patents don’t cover tuber-propagated plants like potatoes or plants found growing wild.

Sometimes a single product qualifies for both utility and design patents. A new kitchen gadget could have its unique functional mechanism protected by a utility patent and its distinctive appearance protected by a design patent.

The Prior Art Search

After confirming your invention meets basic patentability criteria, conduct a thorough prior art search. This isn’t optional—it’s foundational to preparing a strong, defensible patent application and arguably the best investment you can make before spending money on filing fees.

Why a Thorough Search Matters

A comprehensive prior art search serves two primary purposes. First, it helps you make an informed decision about whether to proceed with the costly application process. If the search uncovers prior art that clearly discloses your invention, it saves you from wasting thousands of dollars in non-refundable USPTO fees on an idea that isn’t patentable.

Second, search results are invaluable for drafting the patent application itself. By understanding the existing landscape of similar inventions, patent claims can be written strategically to highlight novel and non-obvious features, increasing the likelihood of the patent being granted.

The USPTO Seven-Step Strategy

The USPTO provides a formal seven-step strategy that mirrors the process used by its own examiners. Following this structured approach is far more effective than performing simple keyword searches.

Step 1: Brainstorm Keywords and Technical Terms

Write a concise, accurate description of your invention. Focus on its purpose (what it does), composition (what it’s made of), and use (how it’s used). Brainstorm keywords, technical terms, and synonyms. Avoid overly broad terms like “device,” “system,” or “process.”

For an improved umbrella, terms might include “parasol,” “windproof,” “rib assembly,” and “canopy support.”

Step 2: Find Relevant CPC Classifications

Use your keywords to search the Cooperative Patent Classification (CPC) system on the USPTO website. The CPC is a detailed international system that categorizes inventions by technical subject matter, not by specific words used to describe them.

This step is crucial because inventors often use different terminology to describe similar concepts. A classification search can uncover relevant patents that keyword searches would miss.

Step 3: Verify the Classifications

Review the official definitions of potentially relevant CPC codes. These definitions, available on the USPTO website, clarify each classification’s scope and ensure you’re searching in the correct technical area.

Steps 4 & 5: Search U.S. Patents and Review In-Depth

Using verified CPC codes, search the USPTO’s Patent Public Search tool. This generates a list of all granted U.S. patents assigned to that classification.

Carefully review the front page, abstract, and drawings of each patent to identify the most relevant ones. Then conduct in-depth reviews of selected patents, paying close attention to the claims, which define the legal scope of the patented invention.

Step 6: Search U.S. Published Applications

Repeat the search process using the same CPC codes, but search for published patent applications. These are applications made public but not yet granted as patents. Since March 2001, the U.S. has published most patent applications 18 months after filing. Published applications are also considered prior art.

Step 7: Broaden Your Search

A comprehensive search extends beyond U.S. patent documents. Prior art can exist anywhere in the world. Broaden your search to include:

Foreign Patent Databases: Use tools like the World Intellectual Property Organization’s PatentScope or the European Patent Office’s Espacenet to search patents and applications from other countries.

Non-Patent Literature: Search for relevant disclosures in technical journals, scientific papers, conference proceedings, textbooks, websites, and product catalogs. Inventions can be publicly disclosed in many forms outside patents.

Many inventors naturally start and end their search with simple keywords in a search engine. This approach is often ineffective and can provide false security. Patent language is highly technical and can vary significantly over time. A classification-based search overcomes this limitation.

It’s like searching a library: a keyword search is like shouting a book’s title in the lobby and hoping for the best, while a classification search is like going directly to the correct shelf in the correct section.

Strategic Decisions Before Filing

Before drafting your application, make two critical strategic decisions. These choices regarding legal representation and application type will shape the cost, timeline, and ultimate success of your patenting journey.

Hiring an Attorney vs. Filing Pro Se

Filing a patent application is a formal legal proceeding governed by complex laws and regulations. While any inventor can file on their own behalf—called filing “pro se”—the USPTO strongly recommends engaging a registered patent attorney or patent agent.

The primary value of a patent professional lies in their expertise in claim drafting. Patent claims are the legally enforceable sentences that define the invention’s boundaries. A poorly drafted claim can render a patent worthless, while a skillfully drafted claim can provide broad, robust protection.

Patent attorneys are trained in the specific legal language and strategic nuances required to draft effective claims, navigate the complex examination process, and avoid common but potentially fatal errors like providing insufficient disclosure or using ambiguous terminology. A mistake in a pro se application can permanently damage or forfeit an inventor’s rights.

However, legal representation costs can be a significant barrier for individual inventors and small businesses. The USPTO provides several free resources for those choosing the pro se path. These programs offer procedural guidance but cannot provide legal advice.

USPTO Pro Se Resources

Pro Se Assistance Program: Offers dedicated outreach and education for pro se applicants. Inventors can schedule one-on-one appointments via video conference or telephone for help with questions and filing. Contact: 1-866-767-3848 or [email protected].

Inventors Assistance Center: Staffed by former supervisory patent examiners who answer general questions about patent policy and procedure. Contact: 800-786-9199.

Patent Pro Bono Program: For financially under-resourced inventors meeting specific income criteria, this nationwide program matches them with volunteer patent attorneys providing free legal assistance.

Law School Clinic Certification Program: Several law schools have clinics where law students, under strict faculty supervision, provide free legal help to inventors.

Patent and Trademark Resource Centers: A nationwide network of public, state, and academic libraries with staff trained to assist the public with patent search tools and resources. Find PTRC locations on the USPTO website.

The decision to file pro se shouldn’t be taken lightly. While the USPTO provides valuable resources to make the process more accessible, they’re intended to help you file a high-quality application, not replace strategic legal counsel. Filing on your own is a significant assumption of legal risk, where seemingly minor mistakes can have permanent, costly consequences.

Provisional vs. Non-Provisional Applications

The second major strategic decision is whether to begin with a provisional patent application (PPA) or file a non-provisional patent application (NPA) directly. This isn’t a choice between “good” and “bad” applications, but a strategic decision based on your invention’s development stage, budget, and timeline.

The PPA Trap

The low cost and informality of a PPA can be appealing, but they hide a significant pitfall. A provisional application only secures a priority date for the subject matter it fully discloses.

Many inventors make the devastating mistake of filing a brief or incomplete PPA, believing it’s just a rough draft that can be improved later in the non-provisional application. This is incorrect. Any new information added to the non-provisional application won’t receive the benefit of the PPA’s early filing date.

If a competitor published a similar invention during that year, the publication could invalidate patent claims related to the new information. One court case demonstrated how a patent was invalidated because the provisional application failed to describe the specific angle of a drill bit—a seemingly minor detail that proved fatal.

A provisional application should be drafted with the same level of detail and completeness as a non-provisional application. The only components that can be omitted are formal claims, the oath, and the information disclosure statement.

Drafting Your Patent Application

Drafting a patent application is highly technical legal writing. Every section, sentence, and word choice has specific purpose and can have significant legal consequences. A complete non-provisional application consists of several distinct components, each with strict formatting requirements.

The Specification: Teaching the World Your Invention

The specification is the written description of your invention. It’s the “what you give” in the patent bargain. In exchange for the government granting a limited-term monopoly, you must teach the public how to make and use the invention in full, clear, exact terms that allow a person of ordinary skill in the relevant field to replicate it without “undue experimentation.”

Withholding key details or leaving “black box” gaps in the description can lead to application rejection or issued patent invalidation.

The specification must follow strict formatting rules, including 8.5 by 11-inch paper with specific margins, 1.5 or double-spaced lines, and clear, non-script font of at least 12-point size. It’s organized into several required sections in the following order:

Title of the Invention: The title should be short, specific, and technically accurate, clearly indicating the invention’s subject matter.

Cross-Reference to Related Applications: If the application claims benefit of an earlier-filed application (such as a provisional), that relationship must be stated here or in a separate Application Data Sheet.

Statement Regarding Federally Sponsored Research: If the invention was made with U.S. government funding, a statement must disclose this fact and the government’s rights in the invention.

Background of the Invention: This section sets the stage for your invention. It should describe the general technical field and discuss existing prior art, pointing out specific problems or shortcomings that your new invention is designed to solve. A common mistake is spending too much time describing what’s old and not enough explaining what’s new.

Brief Summary of the Invention: This provides a concise overview of the invention’s substance. It should explain what the invention is and how it addresses the problems outlined in the background section.

Brief Description of the Drawings: If the application includes drawings, this section must list all figures with brief descriptions of what each view depicts (e.g., “FIG. 1 is a top plan view of the device;” “FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1.”).

Detailed Description of the Invention: This is the core of the entire application. It must provide thorough explanation of the invention’s structure, components, and operation. Every part shown in drawings must be mentioned in the description and referred to by its reference numeral (e.g., “the motor 10 is connected to the shaft 12 via the gearbox 14…”).

The description must be complete enough to enable a skilled person to make and use the invention. It must also disclose the “best mode”—the best way of practicing the invention known to you at the time of filing.

The Claims: Defining Your Legal Property Line

While the specification teaches the invention, claims define the legal property rights. As one famous court decision noted, “The name of the game is the claim.” Claims are numbered, single-sentence paragraphs at the end of the specification that precisely define the boundaries of the invention being protected. Anything not recited in a claim isn’t legally protected.

Claims are structured as either independent or dependent:

Independent Claims are the broadest claims. They stand alone and recite the invention’s essential elements without reference to any other claim.

Dependent Claims refer back to a preceding claim (either independent or another dependent claim) and add further limitations or details. For example, a dependent claim might read, “The apparatus of claim 1, wherein the handle is made of rubber.” This incorporates all elements of claim 1 and adds a new limitation. Dependent claims provide narrower, fallback positions if the broader independent claim is found unpatentable.

Claim Language Structure

Claims follow highly structured language:

They begin with a preamble identifying the invention’s category (e.g., “An apparatus for…”, “A method of…”, “A composition comprising…”).

This is followed by a transitional phrase. The word “comprising” is almost universally used. It’s “open-ended,” meaning a product that includes all recited elements plus additional, unrecited elements would still infringe the claim. In contrast, “consisting of” is “closed-ended” and means a product infringes only if it has exactly the recited elements and nothing more. Using “comprising” ensures the broadest possible protection.

The body of the claim lists individual elements or steps of the invention and describes how they’re connected or related.

Strategic Drafting Approach

A powerful strategy used by experienced patent professionals is drafting claims first, before writing the detailed description. This counterintuitive workflow helps ensure the application’s legal integrity.

By finalizing claim language first, the drafter creates a definitive checklist of every term and element that must be fully supported in the specification. The detailed description can then be written to methodically explain each claimed element, providing clear “antecedent basis” for every term used in claims and ensuring the specification robustly supports the invention’s full legal scope.

This approach transforms drafting from a simple narrative exercise into strategic legal construction, significantly reducing the risk of fatal flaws.

Drawings and Abstract

Drawings must be submitted if they’re necessary to understand the invention. They’re not just illustrations—they’re a formal part of the disclosure. The USPTO has strict formatting requirements: they must be in black and white (unless a special petition for color drawings is granted), use India ink or equivalent, contain reference numerals for all parts mentioned in the description, and follow specific margin and labeling rules.

Common mistakes that can lead to USPTO objections include using lines too light for reproduction, incorrect labeling, or including excessive text within the drawing itself.

Abstract The application must include an abstract of the disclosure. This is a brief summary, limited to a single paragraph of 150 words or less, starting on a separate page. Its purpose is allowing the public and USPTO staff to quickly determine the nature of the invention’s technical disclosure.

Filing Your Application with the USPTO

Once application documents are drafted, the next phase involves practical, administrative steps of submitting them to the USPTO and paying required fees. This is primarily done through the agency’s online portal, Patent Center.

Getting Started with Patent Center

The USPTO’s official portal for electronic filing and management of patent applications is Patent Center. While it’s possible to file as an unregistered guest user, creating a registered account is necessary to access the full suite of tools, including viewing application status, responding to office communications, and managing the application throughout its lifecycle.

The setup process can be an unexpected administrative hurdle and should be treated as a critical step. It involves multiple stages and third-party verification.

Step 1: Create a USPTO.gov Account

First, create a general account at the MyUSPTO portal.

Step 2: Verify Your Identity with ID.me

To ensure system security, the USPTO requires all registered users to verify their identity through a trusted third-party service called ID.me. This mandatory step for secure access involves providing sensitive personal information. The process typically requires:

• A government-issued photo ID (such as a driver’s license or passport)
• A Social Security Number
• A computer or smartphone with a camera, as you’ll be prompted to take a “selfie” matched against your photo ID

Alternatively, applicants who don’t wish to use the online ID.me service can complete a paper-based verification form, which must be notarized and mailed to the USPTO, though this process can take up to 10 business days.

Step 3: Self-Enroll in Patent Center

After your identity is verified, log in to Patent Center and complete the self-enrollment process. This links your verified identity to your role as an inventor or patent practitioner, granting full, secure access to the system.

The Electronic Filing Process

Patent Center provides a modern, web-based interface for uploading application documents. It features a drag-and-drop system allowing multiple files to be uploaded at once.

A critical requirement for filing a non-provisional utility application is document format. To avoid a substantial surcharge, the specification—including description, claims, and abstract—must be submitted in DOCX format. This allows USPTO systems to better process and search the application text.

Other documents, such as the inventor’s oath/declaration and drawings, are typically submitted as PDF files. The USPTO provides numerous resources, including video tutorials and user guides, to assist filers with the DOCX submission process.

Understanding and Paying Fees

Filing a patent application involves several government fees, which are non-refundable regardless of whether a patent is ultimately granted. For a non-provisional utility application, three main fees are due at filing: a basic filing fee, a search fee (covering the examiner’s prior art search cost), and an examination fee (covering substantive review cost).

The total amount depends heavily on your entity status. The USPTO offers significant discounts to encourage participation from individual inventors and small businesses. There are three tiers:

Large Entity: Standard, full fee amount.

Small Entity: Applicants qualifying as a small entity—defined as an individual, non-profit organization, or business with fewer than 500 employees—receive a 60% reduction on most fees.

Micro Entity: This status provides the largest discount (80% reduction) and is reserved for individual inventors with low income who haven’t been named as inventor on more than four previously filed patent applications. This status requires filing a special certification form with the USPTO.

The table below provides a sample of key fees. However, fees are subject to change, and applicants must always consult the official USPTO Fee Schedule for current amounts before filing.

Note: Fees are based on the USPTO Fee Schedule as of early 2025 and are for illustrative purposes. All fees are subject to change.

Patent Prosecution: The Examination Process

Filing the application is only the beginning. What follows is a period of back-and-forth negotiation with the USPTO known as “patent prosecution.” This is where the application is scrutinized by a patent examiner and you (or your attorney) must defend its patentability.

What is Patent Prosecution?

After an application is filed and deemed complete, it’s assigned to a USPTO patent examiner with technical expertise in your invention’s field. The examiner conducts their own independent prior art search and reviews the application to ensure it complies with all U.S. patent laws and regulations.

This rigorous examination process typically takes one to three years to complete. It’s very rare for a patent application to be allowed as originally filed—most applications receive at least one rejection that must be overcome.

This phase shouldn’t be viewed as a simple pass/fail test, but rather as formal negotiation. The examiner’s role is ensuring the patent, if granted, is valid and doesn’t cover more than what you’re legally entitled to protect. Your role is arguing for the broadest possible protection supported by your disclosure.

Responding to an Office Action

The primary vehicle for communication from the examiner is the Office Action. This official letter details all legal and formal issues the examiner has identified with your application. An Office Action isn’t the end of the process—it’s the start of negotiation.

Issues raised fall into two main categories:

Objections relate to formal requirements of the application, such as incorrectly formatted drawings, non-compliant abstracts, or errors in the specification. These are typically straightforward to correct.

Rejections are substantive legal denials of one or more patent claims. The most common rejections are based on lack of novelty (under 35 U.S.C. § 102) or, more frequently, non-obviousness (under 35 U.S.C. § 103).

Office Actions are typically designated as either non-final or final:

A Non-Final Office Action is the first time the examiner raises a particular set of rejections. You have a set period (usually three months, extendable to six months with extension fees) to file a written response.

A Final Office Action is issued if your response to the non-final action fails to resolve all outstanding issues. The term “final” can be misleading—it doesn’t necessarily mean the application is dead. It’s a procedural term indicating this round of negotiation has concluded and your response options are now more limited.

Crafting Your Response

A complete response to an Office Action must address every single objection and rejection raised by the examiner. The two primary tools for responding are:

Arguments: Presenting legal and technical arguments explaining why the examiner’s position is incorrect. This could involve arguing that the examiner misinterpreted a prior art reference or that the combination of references they cited wouldn’t have been obvious.

Amendments: Modifying patent claim language to narrow their scope and distinguish them from prior art cited by the examiner. For example, if a broad claim is rejected, you can add more specific details to the claim to make it patentable.

Navigating a Final Rejection

Receiving a Final Office Action requires a strategic decision. The primary options for moving forward are:

File an After-Final Response: In some cases, you can file a response making minor amendments that place the application in condition for allowance, often after discussing with the examiner.

File a Request for Continued Examination (RCE): This is a very common strategy. By filing an RCE and paying an additional fee, you can effectively “re-open” prosecution, allowing submission of further amendments and arguments. This essentially resets the negotiation and returns the application to non-final status.

File an Appeal: If you believe the examiner made a clear error in their legal reasoning and further negotiation is unlikely to be productive, you can appeal the rejection. The appeal goes to an independent administrative body within the USPTO called the Patent Trial and Appeal Board (PTAB), which will review the examiner’s decision.

After the Grant: Maintaining and Enforcing Your Patent

Securing an issued patent is a major accomplishment, but the responsibilities of a patent owner don’t end there. The final phase involves paying the issue fee, maintaining the patent’s validity through periodic payments, and enforcing patent rights against infringers.

Receiving Your Patent Grant

If the examiner determines all claims in your application are allowable, they’ll issue a Notice of Allowance. This official notice indicates the patent is ready to be granted, pending payment of a final issue fee. You must pay this fee by the deadline specified in the notice. Once paid, the USPTO will officially grant the patent and publish it, making it a fully enforceable legal right.

Maintaining Your Patent

For utility patents, the grant is conditional upon ongoing payment of periodic maintenance fees. These fees are required to keep the patent in force for its full 20-year term. Failure to pay a maintenance fee on time will result in the patent expiring, and the invention will fall into the public domain.

The payment schedule is based on the anniversary of the patent’s grant date:

• First maintenance fee: due at 3.5 years after grant
• Second fee: due at 7.5 years
• Third and final fee: due at 11.5 years

The USPTO provides a six-month grace period after each deadline during which the fee can still be paid, but a significant surcharge is added. Payments can be made online through the USPTO’s Patent Maintenance Fees Storefront.

Design and plant patents don’t require maintenance fees.

Patent Enforcement Basics

A patent isn’t self-enforcing. The USPTO grants the patent but doesn’t monitor the marketplace for infringement or take action on your behalf. You bear the full responsibility and considerable expense of enforcing your rights.

Typical steps in patent enforcement include:

Monitoring and Detection: You must actively watch the market to identify products or processes that may be infringing your patent claims.

Negotiation and Licensing: The most common first step is contacting the potential infringer and attempting to negotiate a licensing agreement. Under such an agreement, the infringer pays you a royalty in exchange for the right to legally practice the invention.

Cease-and-Desist Letter: If negotiations aren’t desired or are unsuccessful, your attorney will typically send a formal cease-and-desist letter demanding that the infringing activity stop immediately.

Litigation: As a last resort, you can file a patent infringement lawsuit in federal district court. Patent litigation is notoriously complex, time-consuming, and extremely expensive, often costing millions of dollars.

When sued for infringement, an accused infringer’s most common defense strategy is attacking the patent’s validity itself. They’ll argue the USPTO made a mistake and should never have granted the patent, typically by presenting prior art they believe shows the invention wasn’t novel or was obvious. If a court agrees and declares the patent invalid, you lose all exclusive rights.

Correcting Errors in an Issued Patent

Occasionally, an error is discovered in a patent after it’s been granted. The USPTO provides two primary mechanisms for correction, and choosing the correct one is critical.

Certificate of Correction (CoC) is the appropriate tool for fixing minor, non-substantive errors. This includes typographical errors, clerical mistakes made by the applicant, or errors introduced by the USPTO during printing. A CoC can’t be used to make any change that would alter the scope of patent claims. For example, correcting a misspelled inventor’s name would be done with a CoC.

Reissue Application is a much more complex procedure used to correct substantive errors that render the patent “wholly or partly inoperative or invalid.” This includes situations where claims are too broad (they cover prior art) or too narrow (they fail to cover the full scope of the disclosed invention), or where there are significant inaccuracies in the specification or drawings. A reissue application to broaden claim scope must be filed within two years of the original patent’s grant date.

The Reissue Risk

Filing a reissue application is a high-risk strategic decision. The term “reissue” is misleading—it’s not a simple administrative fix. When you file a reissue application, you must surrender your original patent to the USPTO.

The application then undergoes completely new, often more rigorous examination by a specialized team of senior examiners. These examiners will conduct a new prior art search and can raise new rejections.

It’s possible that in trying to correct a minor error or broaden claims, examiners will uncover new prior art that invalidates not only the new claims but also the original, already-granted claims. In attempting to strengthen your patent, you could inadvertently end up with a much weaker patent or no patent at all.

Reissue should be considered not as a simple correction, but as a “do-over” of the entire prosecution, with all the associated risks.

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