Inventorship

The statute defines the inventor as the individual or, if a joint invention, the individuals collectively who invented or discovered the subject matter of the invention. A joint inventor, or coinventor, is any one of the individuals who invented or discovered the subject matter of a joint invention (35 U.S.C. 100(f) and (g))¹.

The MPEP states that the threshold question in determining inventorship is who conceived the invention, and that unless a person contributes to the conception of the invention, he is not an inventor. Reduction to practice, per se, is irrelevant to defining an inventor, with an exception for simultaneous conception and reduction to practice². The inventor or joint inventors named must be natural persons, that is, human beings².

In an application for a patent, each individual who is the inventor or a joint inventor of a claimed invention must execute an oath or declaration, except as otherwise provided (35 U.S.C. 115(a)), in applications filed on or after September 16, 2012³. In examination, the USPTO generally presumes that the inventors named on the application data sheet or oath or declaration are the actual inventors⁶. The MPEP is Revision 01.2024, and the USPTO notes that later changes to examining policy are listed separately from it^2,10.

In University of Pittsburgh v. Hedrick (Fed. Cir. 2009) the Federal Circuit stated that conception is the touchstone of inventorship under 35 U.S.C. 116. It defined conception as the formation in the mind of the inventor of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice⁴.

• The test. The idea must be definite and permanent enough that one skilled in the art could understand the invention⁴.
• Proof. The inventor must prove conception by corroborating evidence, preferably contemporaneous disclosures, and the evidence is taken as a whole⁴.
• Working is not required for conception. An inventor need not know that the invention will work. The discovery that it actually works is part of reduction to practice⁴.
• Presumption and burden. The inventors named in an issued patent are presumed correct, and a party alleging misjoinder of inventors must prove its case by clear and convincing evidence⁴.

Inventors may apply for a patent jointly even though they did not physically work together or at the same time, each did not make the same type or amount of contribution, or each did not make a contribution to the subject matter of every claim (35 U.S.C. 116(a))⁵. The MPEP states that a person who shares in the conception of a claimed invention is a joint inventor of that invention, and that the inventive entity for an application is based on some contribution to at least one of the claims by each named joint inventor². In a joint invention, each inventor must contribute to the joint arrival at a definite and permanent idea of the invention⁴.

The USPTO's 2025 guidance quotes the Federal Circuit's Pannu test for joint inventors: each purported inventor must contribute in some significant manner to the conception or reduction to practice of the invention, make a contribution to the claimed invention that is not insignificant in quality when measured against the full invention, and do more than merely explain to the real inventors well-known concepts or the current state of the art⁶. If a joint inventor refuses to join in an application or cannot be found after diligent effort, the other inventor may make the application on behalf of himself and the omitted inventor (35 U.S.C. 116(b))⁵.

• In a pending application. If through error a person is named as an inventor, or an inventor is not named, the Director may permit the application to be amended on such terms as the Director prescribes (35 U.S.C. 116(c))⁵.
• In an issued patent. The Director may issue a certificate correcting the error on application of all the parties and assignees, with proof of the facts and such other requirements as may be imposed (35 U.S.C. 256(a))⁷.
• Validity. The error of omitting inventors or naming persons who are not inventors does not invalidate the patent if it can be corrected under section 256. A court may order correction on notice and hearing of all parties concerned (35 U.S.C. 256(b))⁷.

The USPTO guidance also says an application listing an AI system or other non-natural person as an inventor should be rejected under 35 U.S.C. 101 and 115 or other appropriate action, and that a priority claim to a foreign application naming an AI tool as the sole inventor will not be accepted⁶. The USPTO's list of publications subsequent to the MPEP, current as of July 20, 2026, includes the November 2025 notice¹⁰; check uspto.gov for anything newer. The guidance is examination guidance, not a court decision, and the Federal Circuit left the AI-assistance question open in Thaler^6,8.