What is the legal basis for rejecting claims due to undue multiplicity?

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 legal basis for rejecting claims due to undue multiplicity is primarily 35 U.S.C. 112(b) (or pre-AIA 35 U.S.C. 112, second paragraph). As stated in MPEP 2173.05(n):

“Undue multiplicity rejections based on 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, should be applied judiciously and should be rare.”

This rejection is based on the requirement that claims must particularly point out and distinctly claim the subject matter which the inventor regards as the invention. When claims are unduly multiplied, they may fail to meet this requirement by creating confusion rather than clarity.

Additionally, the MPEP cites case law supporting this approach, including In re Chandler, 319 F.2d 211, 225, 138 USPQ 138, 148 (CCPA 1963), which emphasizes the need for a “rule of reason” in applying such rejections.