The Manual of Patent Examining Procedure (MPEP) is published by the United States Patent and Trademark Office (USPTO) for use by patent attorneys and agents and patent examiners. It describes all of the laws and regulations that must be followed in the examination of U.S. patent applications, and articulates their application to an enormous variety of different situations. The MPEP is based on Title 37 of the Code of Federal Regulations, which derives its authority from Title 35 of the United States Code, as well as on case law arising under those titles. The first version of the MPEP was published in 1920 by the Patent and Trademark Office Society.

The MPEP is used extensively by patent attorneys and agents to help make sure they and Examiners follow the proper USPTO regulations. The USPTO registration examination tests knowledge of the MPEP and the underlying laws and regulations.

The MPEP is available in both PDF and HTML versions. The current version of the MPEP is the 9th Edition, which was released in March 2014. The MPEP has traditionally been available in paper form, but electronic versions are now used more often, particularly because an applicant only may consult the electronic versions while taking the USPTO registration examination, or the patent bar examination. As of March, 2014 the patent bar examination tests the 9th Edition.

The MPEP provides guidance to members of the public on how to present persuasive arguments to a patent examiner as to why a patent should be granted on a given patent application. See in particular Chapter 2100 on patentability.