What is the one-year rule in pre-AIA 35 U.S.C. 135(b)?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The one-year rule in pre-AIA 35 U.S.C. 135(b) sets time limits for making claims that are the same as, or for substantially the same subject matter as, claims in an issued patent or published application. Specifically:

• For issued patents: A claim cannot be made in any application unless it’s made prior to one year from the date on which the patent was granted.
• For published applications: A claim cannot be made in an application filed after the publication unless it’s made before 1 year after the date on which the application is published.

The MPEP clarifies that “the expression ‘prior to one year from the date on which the patent was granted’ in 35 U.S.C. 135(b) includes the one-year anniversary date of the issuance of a patent.”

If these time limits are not met, an interference will not be declared unless there was a claim for “substantially the same subject matter” within the time limit.