37 CFR § 42.120 - Patent owner response.

---
identifier: "/us/cfr/t37/s42.120"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "37 CFR § 42.120 - Patent owner response."
title_number: 37
title_name: "Patents, Trademarks, and Copyrights"
section_number: "42.120"
section_name: "Patent owner response."
chapter_name: "UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE"
subchapter_number: "A"
subchapter_name: "GENERAL"
part_number: "42"
part_name: "TRIAL PRACTICE BEFORE THE PATENT TRIAL AND APPEAL BOARD"
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), 3, 6, 21, 23, 41, 134, 135, 143, 153, 311, 312, 314, 316, 318, 321-326, 328; Pub. L. 112-29, 125 Stat. 284; and Pub. L. 112-274, 126 Stat. 2456."
regulatory_source: "77 FR 48669, Aug. 14, 2012, unless otherwise noted."
cfr_part: "42"
---


# 42.120 Patent owner response.

(a) *Scope.* A patent owner may file a single response to the petition and/or decision on institution. A patent owner response is filed as an opposition and is subject to the page limits provided in § 42.24.

(b) *Due date for response.* If no time for filing a patent owner response to a petition is provided in a Board order, the default date for filing a patent owner response is three months from the date the *inter partes* review was instituted.

[77 FR 48727, Aug. 14, 2012, as amended at 85 FR 79129, Dec. 9, 2020]