What’s the difference between statutory and nonstatutory 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 main differences between statutory and nonstatutory double patenting are:

• Statutory double patenting: Based on 35 U.S.C. 171, it applies when identical designs with identical scope are claimed twice. It cannot be overcome by a terminal disclaimer.
• Nonstatutory double patenting: Based on judicial doctrine, it applies to designs with different appearances or differing scope that are patentably indistinct. It can be overcome by filing a terminal disclaimer.

The MPEP states: A “same invention” type double patenting rejection, whether statutory or nonstatutory, cannot be overcome by a terminal disclaimer. However, for nonstatutory double patenting: Nonstatutory categories of double patenting rejections which are not the “same invention” type may be overcome by the submission of a terminal disclaimer.