MPEP 2301
Interference Proceedings

Ninth Edition of the MPEP, Revision 07.2022, Last Revised in February 2023

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2301    Interference Proceedings [R-08.2017]

An interference is a contest under pre-AIA 35 U.S.C. 135(a) between an application and either another application or a patent. An interference is declared to assist the Director of the United States Patent and Trademark Office in determining priority, that is, which party first invented the commonly claimed invention within the meaning of pre-AIA 35 U.S.C. 102(g)(1). See MPEP § 2301.03. Once an interference has been suggested under 37 CFR 41.202, the examiner refers the suggested interference to the Board. An administrative patent judge declares the interference, which is then administered at the Board. A panel of Board members enters final judgment on questions of priority and patentability arising in an interference.

Once the interference is declared, the examiner generally will not treat the application again until the interference has been terminated. Occasionally, however, the Board may refer a matter to the examiner or may consult with the examiner on an issue. Given the very tight deadlines in an interference, any action on a consultation or referral from the Board must occur with special dispatch.

The application returns to the examiner after the interference has been terminated. Depending on the nature of the judgment in the case, the examiner may need to take further action in the application. For instance, if there are remaining allowable claims, the application may need to be passed to issue. The Board may have entered a recommendation for further action by the examiner in the case. If the applicant has lost an issue in the interference, the applicant may be barred from taking action in the application or any subsequent application that would be inconsistent with that loss.

Given the infrequency, cost, and complexity of interferences and derivation proceedings, it is important for the examiner to consult immediately with an Interference Practice Specialist (IPS) in the examiner’s Technology Center, see MPEP § 2302, once a possible interference is identified. It is also important to complete examination before the possible interference is referred to the Board. See MPEP § 2303. See MPEP § 2310 et seq. for discussion of derivation proceedings.