Can inoperative prior art be used in 35 U.S.C. 103 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.

Yes, inoperative prior art can be used in 35 U.S.C. 103 rejections for obviousness. The MPEP Section 2121.01 clearly states:

“Even if a reference discloses an inoperative device, it is prior art for all that it teaches.”

This principle is supported by case law, as the MPEP further explains:

“Therefore, ‘a non-enabling reference may qualify as prior art for the purpose of determining obviousness under 35 U.S.C. 103.’”

This means that even if a prior art reference doesn’t fully enable the invention, it can still be used to show that the claimed invention would have been obvious to a person of ordinary skill in the art.