Can an inventor’s testimony alone prove conception in a patent case?

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.

Can an inventor’s testimony alone prove conception in a patent case?

While an inventor’s testimony is important, it is generally not sufficient on its own to prove conception in a patent case. The MPEP 2138.04 states:

“An inventor’s testimony, standing alone, is insufficient to prove conception, as some form of corroboration is required.”

This requirement for corroboration serves several purposes:

• It helps verify the accuracy of the inventor’s recollection
• It protects against fraudulent claims
• It ensures that the conception date is supported by objective evidence

Corroborating evidence can come in various forms, such as contemporaneous documents, witness testimony, or physical exhibits. The key is that there must be some independent evidence that supports the inventor’s claim of conception beyond their own statement.