What are the requirements for filing an affidavit or declaration under 37 CFR 1.131(a)?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

An affidavit or declaration under 37 CFR 1.131(a) may be necessary even when there is common ownership between a reference and an application. According to MPEP 715.01(b):

The mere fact that the reference patent or application publication which shows but does not claim certain subject matter and the application which claims it are owned by the same assignee does not avoid the necessity of filing an affidavit or declaration under 37 CFR 1.131(a), in the absence of a showing under 37 CFR 1.132 that the patentee derived (in the context of pre-AIA law) the subject matter relied on from the inventor (MPEP § 716.10).

This means that an inventor may need to file an affidavit or declaration to establish prior invention, even if there is common ownership. The requirements for such an affidavit typically include:

• Evidence of conception of the invention before the effective date of the reference
• Evidence of diligence in reducing the invention to practice
• Or, evidence of actual reduction to practice before the effective date of the reference

It’s important to consult the specific requirements in MPEP 715 and work with a patent professional to ensure all necessary elements are included in the affidavit or declaration.