What is the impact of restriction requirement withdrawal on 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.

The withdrawal of a restriction requirement can have significant implications for double patenting issues in patent applications. According to MPEP 821.04(a):

“Once a restriction requirement is withdrawn, the provisions of 35 U.S.C. 121 are no longer applicable. See In re Ziegler, 443 F.2d 1211, 1215, 170 USPQ 129, 131-32 (CCPA 1971). See also MPEP § 804.01.”

This means that the safe harbor provision of 35 U.S.C. 121, which normally protects against double patenting rejections in divisional applications, no longer applies once the restriction requirement is withdrawn. Consequently, claims in related applications may be subject to double patenting rejections if they are not patentably distinct from the claims in the application where the restriction was withdrawn.