CFR›Title 37›Chapter I›Part 41 ContainsSubparts A–ECorpusDaily eCFRDisplayed edition2026-04-24Last updated2026-04-24 PART 41—PRACTICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Subparts A Subpart A—General Provisions Sections 41.1–41.20 B Subpart B—<em>Ex Parte</em> Appeals Sections 41.30–41.54 C Subpart C—<em>Inter Partes</em> Appeals Sections 41.60–41.81 D Subpart D—Contested Cases Sections 41.100–41.158 E Subpart E—Patent Interferences Sections 41.200–41.208 Authority35 U.S.C. 2(b)(2), 3(a)(2)(A), 21, 23, 32, 41, 134, 135, and Public Law 112-29.Source69 FR 50003, Aug. 12, 2004, unless otherwise noted. Previous 11 Part 11—Representation of Others Before the United States Patent and Trademark Office Next 42 Part 42—Trial Practice Before the Patent Trial and Appeal Board