How does the 35 U.S.C. 121 prohibition affect statutory double patenting rejections?

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 35 U.S.C. 121 prohibition does not affect statutory double patenting rejections. The MPEP clarifies:

“The 35 U.S.C. 121 prohibition against certain nonstatutory double patenting rejections does not apply to statutory double patenting rejections under 35 U.S.C. 101 of claims to the ‘same invention.’“

In cases where the claims of the second application are drawn to the “same invention” as the first application or patent, a statutory double patenting rejection under 35 U.S.C. 101 should be made. The term “same invention” means identical subject matter. In such cases, it is not necessary to determine whether the 35 U.S.C. 121 prohibition against making double patenting rejections is applicable, as the statutory rejection takes precedence.