37 CFR § 41.203 - Declaration.

---
identifier: "/us/cfr/t37/s41.203"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "37 CFR § 41.203 - Declaration."
title_number: 37
title_name: "Patents, Trademarks, and Copyrights"
section_number: "41.203"
section_name: "Declaration."
chapter_name: "UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE"
subchapter_number: "A"
subchapter_name: "GENERAL"
part_number: "41"
part_name: "PRACTICE BEFORE THE PATENT TRIAL AND APPEAL BOARD"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "35 U.S.C. 2(b)(2), 3(a)(2)(A), 21, 23, 32, 41, 134, 135, and Public Law 112-29."
regulatory_source: "69 FR 50003, Aug. 12, 2004, unless otherwise noted."
cfr_part: "41"
---


# 41.203 Declaration.

(a) *Interfering subject matter.* An interference exists if the subject matter of a claim of one party would, if prior art, have anticipated or rendered obvious the subject matter of a claim of the opposing party and vice versa.

(b) *Notice of declaration.* An administrative patent judge declares the patent interference on behalf of the Director. A notice declaring an interference identifies:

(1) The interfering subject matter;

(2) The involved applications, patents, and claims;

(3) The accorded benefit for each count; and

(4) The claims corresponding to each count.

(c) *Redeclaration.* An administrative patent judge may redeclare a patent interference on behalf of the Director to change the declaration made under paragraph (b) of this section.

(d) A party may suggest the addition of a patent or application to the interference or the declaration of an additional interference. The suggestion should make the showings required under § 41.202(a) of this part.