Can new matter be added to a divisional application?

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.

No, new matter cannot be added to a divisional application. The divisional application must only contain subject matter disclosed in the parent application. The MPEP clearly states:

Thus the disclosure presented in a divisional application must not include any subject matter which would constitute new matter if submitted as an amendment to the parent application.

Any attempt to add new matter to a divisional application will be rejected under 35 U.S.C. 112(a) as lacking written description support in the parent application.