Terms and Concepts

Certificate of Reexamination

A reexamination proceeding is concluded by publication of a reexamination certificate.  The certificate amends the text of the patent that was reexamined, in a manner analogous to a certificate of correction.  The reexamination certificate will contain the text of all changes to the text of the patent that was the subject of the reexamination proceeding (MPEP 2288 and 2290).

Upon completion of a PTO reexamination proceeding, the Commissioner will issue and publish a certificate canceling any claim finally determined not to be patentable, confirming any claim determined to be patentable, and incorporating any amended or new claim determined to be patentable. These certificates are the same for normal or reissue patents.


Reexamination certificates were first authorized on December 19, 1981. They first appeared in 1985. The drawing, which appears on the front page, is to be indexed as a drawing. The appearance of a drawing on the front page is only to be indexed as a drawing page for reexamination corticated and reexamination of reissues. A reexamination certificate may be issued on any type of patent (utility, design, plant etc.).

The reexamination certificate is formatted much like the title page of current U.S. patents and includes the patent number of the original patent preceded by the letter “B” or “C” and the number of the reexamination proceeding of that patent: 1, 2, or 3, etc. This certificate will specify the claims confirmed as patentable and those canceled. Any new claims and any amended claims will be printed indicating the amendments. Any prior court decisions will be identified, as well as the citation of the court decisions.