Can affidavits be used in inter partes reexamination?

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.

Yes, affidavits can be used in inter partes reexamination proceedings. The MPEP states:

“Affidavits under 37 CFR 1.131(a) and 1.132 may be utilized in a reexamination proceeding.”

However, there are limitations on the use of certain types of affidavits:

“Note, however, that an affidavit under 37 CFR 1.131(a) may not be used to ‘swear behind’ a reference patent if the reference patent is claiming the same invention as the patent undergoing reexamination.”

In such cases, the patent owner may consider other options:

• Filing an affidavit under 37 CFR 1.131(c) (see MPEP § 718)
• Initiating an interference proceeding via an appropriate reissue application (see MPEP § 1449.02)

Patent owners and third-party requesters should carefully consider the appropriate use of affidavits in inter partes reexamination to support their positions.