What is the role of “long-felt need” in patent non-obviousness arguments?

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.

“Long-felt need” is an important secondary consideration that can support an argument for non-obviousness in patent applications. It suggests that the invention addresses a problem that has existed for a significant time without a solution. The MPEP 716.01(b) emphasizes the importance of establishing a nexus:

“Nexus is a legally and factually sufficient connection between the objective evidence and the claimed invention such that the objective evidence should be considered in the determination of nonobviousness.”

To effectively use long-felt need as evidence, an applicant must demonstrate:

• The need has been persistent and recognized by those in the field
• The need has not been satisfied by another before the invention
• The claimed invention actually satisfies the need

Establishing this connection helps show that the invention was not obvious to those skilled in the art, despite the long-standing nature of the problem.