# MPEP § 2301: Interference Proceedings

> Federal · Agency guidance · In force

URL: https://www.frixlaw.com/law-library/statutes/MPEP_S2301

## Section

- **Citation:** MPEP § 2301
- **Heading:** Interference Proceedings
- **Jurisdiction:** Federal
- **Kind:** Agency guidance
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** USPTO MPEP / Chapter 2300 - Interference and Derivation Proceedings / MPEP § 2301

## Text

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
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.

## Nearby sections

- [MPEP § 2301 Interference Proceedings](https://www.frixlaw.com/law-library/statutes/MPEP_S2301.md)
- [MPEP § 2301.01 Statutory Basis](https://www.frixlaw.com/law-library/statutes/MPEP_S2301.01.md)
- [MPEP § 2301.02 Definitions](https://www.frixlaw.com/law-library/statutes/MPEP_S2301.02.md)
- [MPEP § 2301.03 Interfering Subject Matter](https://www.frixlaw.com/law-library/statutes/MPEP_S2301.03.md)
- [MPEP § 2301.04 Applicability of 35 U.S.C. 102(g) to Applications filed on or after March 16, 2013](https://www.frixlaw.com/law-library/statutes/MPEP_S2301.04.md)
- [MPEP § 2302 Consult an Interference Practice Specialist](https://www.frixlaw.com/law-library/statutes/MPEP_S2302.md)
- [MPEP § 2303 Completion of Examination](https://www.frixlaw.com/law-library/statutes/MPEP_S2303.md)
- [MPEP § 2303.01 Issuance and Suspension](https://www.frixlaw.com/law-library/statutes/MPEP_S2303.01.md)
- [MPEP § 2303.02 Other Outstanding Issues with Patents](https://www.frixlaw.com/law-library/statutes/MPEP_S2303.02.md)
- [MPEP § 2304 Suggesting an Interference](https://www.frixlaw.com/law-library/statutes/MPEP_S2304.md)
- [MPEP § 2304.01(a) Interference Search](https://www.frixlaw.com/law-library/statutes/MPEP_S2304.01(a).md)
- [MPEP § 2304.01(b) Obtaining Control Over Involved Files](https://www.frixlaw.com/law-library/statutes/MPEP_S2304.01(b).md)
- [MPEP § 2304.01(c) Translation of Foreign Benefit Application](https://www.frixlaw.com/law-library/statutes/MPEP_S2304.01(c).md)
- [MPEP § 2304.01(d) Sorting Claims](https://www.frixlaw.com/law-library/statutes/MPEP_S2304.01(d).md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/MPEP_S2301. Check the current official text before relying on it. Not legal advice.