37 CFR § 1.907 - reexamination prohibited.

---
identifier: "/us/cfr/t37/s1.907"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "37 CFR § 1.907 - reexamination prohibited."
title_number: 37
title_name: "Patents, Trademarks, and Copyrights"
section_number: "1.907"
section_name: "reexamination prohibited."
chapter_name: "UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE"
subchapter_number: "A"
subchapter_name: "GENERAL"
part_number: "1"
part_name: "RULES OF PRACTICE IN PATENT CASES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "35 U.S.C. 2(b)(2), unless otherwise noted."
regulatory_source: "24 FR 10332, Dec. 22, 1959, unless otherwise noted."
cfr_part: "1"
---


# 1.907 reexamination prohibited.

(a) Once an order to reexamine has been issued under § 1.931, neither the third party requester, nor its privies, may file a subsequent request for *inter partes* reexamination of the patent until an *inter partes* reexamination certificate is issued under § 1.997, unless authorized by the Director.

(b) Once a final decision has been entered against a party in a civil action arising in whole or in part under 28 U.S.C. 1338 that the party has not sustained its burden of proving invalidity of any patent claim-in-suit, then neither that party nor its privies may thereafter request *inter partes* reexamination of any such patent claim on the basis of issues which that party, or its privies, raised or could have raised in such civil action, and an *inter partes* reexamination requested by that party, or its privies, on the basis of such issues may not thereafter be maintained by the Office.

(c) If a final decision in an *inter partes* reexamination proceeding instituted by a third party requester is favorable to patentability of any original, proposed amended, or new claims of the patent, then neither that party nor its privies may thereafter request *inter partes* reexamination of any such patent claims on the basis of issues which that party, or its privies, raised or could have raised in such *inter partes* reexamination proceeding.