What is the exception to all inventors signing 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.

While generally all inventors must sign an affidavit or declaration under 37 CFR 1.131(a), there is an important exception. According to MPEP 715.04:

“An affidavit or declaration under 37 CFR 1.131(a) may be signed by less than all named inventors of an application if it is shown to the satisfaction of the Director that less than all named inventors of an application invented the subject matter of the claim or claims under rejection.”

This exception allows for situations where:

• Only some of the named inventors contributed to the specific claims under rejection
• The inventorship of certain claims differs from the overall application

In such cases, a proper showing must be made to the USPTO Director explaining why not all inventors are signing the affidavit or declaration.