Correcting Inventorship on an Issued Patent (35 U.S.C. § 256)

Correcting inventorship on a patent that has already issued is a routine, well-defined USPTO procedure — but only if the parties agree. Under 35 U.S.C. § 256, an error in who is named as an inventor does not by itself invalidate the patent, provided the error is actually corrected through one of the mechanisms Congress built for that purpose. This guide walks through when correction is needed, the certificate-of-correction process most institutions use, when a reissue application or district-court action is required instead, and why technology transfer offices treat getting inventorship right — or fixed — as more than paperwork.

When Does Inventorship Need to Be Corrected?

Inventorship errors on an issued patent fall into two categories, and the terminology matters because it points to different fixes:

• Nonjoinder — a true inventor was left off the patent. This typically surfaces when someone who contributed to the conception of at least one claim, per the legal test for joint inventorship under 35 U.S.C. § 116, was never listed as an applicant or was dropped during prosecution.
• Misjoinder — someone is named as an inventor who did not actually contribute to the conception of any claim as issued. This is common after claims are narrowed or amended during examination: a person who conceived subject matter that was cancelled or rewritten out of the final claims is no longer, technically, an inventor of what issued.

Both are errors of fact about who conceived the claimed subject matter — not errors about who deserves credit, who did the most work, or who is listed as an author on a related publication. A technology transfer office (TTO) discovers these errors most often during due diligence for a license or acquisition, when claims are amended late in prosecution without inventorship being revisited, or when a dispute among former lab members surfaces years after grant.

Two Legal Pathways to Correct Inventorship After Issuance

Once a patent has issued, there are three routes to fix inventorship, and which one applies depends entirely on whether every named inventor and assignee agrees:

1. Certificate of Correction under 35 U.S.C. § 256 and 37 CFR 1.324 — the fast, administrative path, available only when inventorship is the only error being corrected and nobody disputes the change.
2. Reissue application under 37 CFR 1.171 et seq. — required when an inventor who needs to be added or removed is unavailable, refuses to cooperate, or when correcting inventorship is bundled with other substantive changes to the patent.
3. District court action under 35 U.S.C. § 256(b) — used when inventorship is genuinely contested and needs to be adjudicated; a court can order the USPTO Director to issue the certificate after notice and a hearing to all concerned parties.

Most corrections institutions handle are uncontested — a co-inventor’s name was inadvertently dropped, or a departed collaborator’s claims were cancelled during prosecution — and those go through the certificate-of-correction route below.

The Certificate of Correction Process, Step by Step

The USPTO’s procedure is set out at MPEP § 1481.02, implementing 37 CFR 1.324. For requests filed since the America Invents Act’s inventorship provisions took effect (September 16, 2012), the requirements are notably lighter than they were before — there is no longer a requirement to show the original error occurred “without deceptive intention.” The request must include:

• A statement from each inventor being added and each current named inventor — either agreeing to the requested change, or affirmatively stating they have no disagreement with it. No oath, declaration, or explanation of how the error occurred is required.
• A statement from every assignee of record, complying with 37 CFR 3.73(c), establishing that assignee’s ownership interest and agreeing to the change.
• The completed request form (USPTO form PTO/SB/44 is the form typically used for this purpose).
• The fee set under 37 CFR 1.20(b) (check the USPTO’s current fee schedule, since these amounts are revised periodically).

Because every named inventor and assignee must submit a statement, the requirement cannot be waived by the applicant or assignee alone — all parties have to participate. If even one required party is unavailable or refuses, the certificate-of-correction route is not available, and the assignee has to consider reissue instead.

When a Reissue Application Is Required Instead

A non-broadening reissue application does not require a statement from the inventor being added or removed, which makes it the practical path when:

• An inventor who should be added or removed cannot be located, has died, or refuses to cooperate.
• Correcting inventorship is being done alongside other substantive corrections to the patent (broadened or narrowed claims, for example), which falls outside what a certificate of correction can address.

Reissue is a more involved process — it reopens examination of the patent and carries its own timing and claim-scope rules — and generally warrants patent counsel rather than a self-filed administrative correction.

Contested Inventorship: District Court Under § 256(b)

When the parties genuinely disagree about who conceived the claimed subject matter — not just an administrative oversight, but a real dispute over inventorship — 35 U.S.C. § 256(b) allows any interested party to bring an action in federal district court. After notice and a hearing to all concerned parties, the court can order correction, and the USPTO Director issues the certificate accordingly on receipt of that order. This is the route used when a certificate of correction is impossible because the statements required under 37 CFR 1.324 cannot be obtained by consent.

Why Getting Inventorship Right Matters

Inventorship is not a credit or authorship question — it is a question of legal ownership, and getting it wrong creates risk that compounds the longer it goes uncorrected:

• Patent validity. Section 256(b) provides that an inventorship error “shall not invalidate the patent in which such error occurred if it can be corrected.” That is a safe harbor conditioned on the error actually being fixed — it is not a reason to leave an obviously wrong inventor list uncorrected. An uncorrected error discovered during litigation can still complicate enforcement, and a pattern of inventorship errors handled carelessly can feed into broader challenges to a patent’s prosecution history.
• Ownership and licensing authority. Under U.S. patent law’s default rule (35 U.S.C. § 262), each co-owner of a patent can make, use, sell, and license the invention without the consent of, and without accounting to, the other co-owners, absent an agreement to the contrary. If a true inventor was omitted and never assigned their rights to the institution, that person retains an independent ownership stake they never transferred — meaning they could license the same technology to a competitor without the TTO’s knowledge or consent. Correcting inventorship, and then obtaining a proper assignment from the added inventor, is often the only way to close that gap.
• Diligence and licensing risk. Inventorship problems are a standard item in patent-related due diligence for licensing transactions. An unresolved inventorship question discovered by a prospective licensee’s counsel can stall or kill a deal, or force renegotiation of representations and warranties in the license agreement.
• Downstream corrections get harder, not easier, over time. Locating a former lab member years after they have left the institution, changed employers, or become uncooperative is far more difficult than correcting the record while everyone involved is still reachable and the facts are fresh.

Practical Steps for a Technology Transfer Office

1. Confirm the error is genuinely one of inventorship (who conceived the claimed subject matter) and not a dispute better addressed as an authorship, credit, or compensation-sharing issue among researchers.
2. Identify every currently named inventor, every inventor who needs to be added or removed, and every assignee of record — all of them will need to participate in whichever correction route applies.
3. If everyone agrees, prepare the certificate-of-correction request under 37 CFR 1.324 (statements from inventors and assignees, PTO/SB/44, and the required fee).
4. If an inventor cannot be reached or will not cooperate, consult patent counsel about a reissue application instead of treating the certificate-of-correction route as blocked indefinitely.
5. Once the certificate issues, follow up on any assignment paperwork needed from a newly added inventor — correcting the patent record and securing ownership rights are two separate steps.

Frequently Asked Questions

Is there a deadline for correcting inventorship on an issued patent?

No statutory deadline requires correction by a fixed date after grant. In practice, institutions correct inventorship as soon as an error is identified, both to close the ownership gap described above and because locating and obtaining cooperation from the parties involved only gets harder with time.

Can an inventor be added or removed without the other inventors’ consent?

Not through a certificate of correction — 37 CFR 1.324 requires a statement from every current inventor and every inventor being added, and that requirement cannot be waived. If consent cannot be obtained, the assignee’s options are a reissue application (which does not require a statement from the inventor being added or removed) or, where inventorship is genuinely contested, an action in federal district court under 35 U.S.C. § 256(b).

Does correcting inventorship change the patent’s filing date, priority date, or term?

No. A certificate of correction fixes the named inventors; it does not alter the patent’s filing date, any claimed priority date, or its expiration date.

Is correcting inventorship the same as correcting patent ownership or assignment records?

No, and this is a common point of confusion. Correcting inventorship under 37 CFR 1.324 changes who is listed as an inventor on the patent itself. It does not, by itself, transfer any ownership interest — a newly added inventor who has not separately assigned their rights still holds an independent ownership stake until a valid assignment is executed and, ideally, recorded with the USPTO.

What if correcting inventorship on the application (before grant) would have been simpler?

It usually is. Correcting inventorship before a patent issues is handled under 37 CFR 1.48 during prosecution and is generally simpler than a post-issuance correction. This guide covers the post-issuance case specifically because that is where TTOs most often discover the problem — during licensing diligence or a later dispute, well after the window for the simpler pre-issuance fix has closed.

This guide explains general USPTO procedure under 35 U.S.C. § 256 and is not legal advice. Inventorship determinations and corrections, especially contested ones, should be handled with patent counsel.