What is statutory double patenting?

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.

Statutory double patenting is a rejection based on the requirement in 35 U.S.C. 101 that an inventor may obtain only one patent for the same invention. The MPEP explains:

“35 U.S.C. 101 requires that whoever invents or discovers an eligible invention may obtain only ONE patent therefor. Thus, it prevents two patents issuing on the same invention to the same inventor (i.e., the same inventive entity) or where there is a common (joint) inventor or common applicant/assignee.“

Key points about statutory double patenting:

• It applies when identical subject matter is being claimed in more than one application.
• It forms the basis for statutory double patenting rejections.
• It aims to prevent an inventor or inventive entity from obtaining multiple patents for the same invention.

Examiners use specific form paragraphs (8.30, 8.31, and 8.32) for statutory double patenting rejections. For a detailed discussion on this topic, refer to MPEP § 804.