How is the effective filing date determined for continuation applications?

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.

For continuation applications, the effective filing date is generally determined based on the earliest application in the chain that supports the claimed invention. The MPEP 2152.01 provides guidance on this:

“In the case of a continuation application, continuation-in-part application, or divisional application claiming the benefit of a prior-filed nonprovisional application under 35 U.S.C. 120, 121, or 365(c), the effective filing date will be the filing date of the prior-filed application for any claims that are fully supported by the prior-filed application.”

However, it’s important to note that:

• For claims that are not fully supported by the prior-filed application, the effective filing date will be the actual filing date of the continuation application.
• In continuation-in-part applications, new matter introduced in the CIP application will have the filing date of the CIP as its effective filing date.

This determination is made on a claim-by-claim basis, ensuring that each claim is accorded the appropriate effective filing date based on its support in the application history.