What is the difference between species and restriction requirements?

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.

Species and restriction requirements are related but distinct concepts in patent examination:

• Restriction requirement: Applies when an application contains claims to two or more independent or distinct inventions.
• Species requirement: A type of restriction requirement that applies when an application contains claims to two or more patentably distinct embodiments within a single invention.

According to MPEP 808.01(a), “Where restriction between species is appropriate, the examiner should send a letter including only a restriction requirement.” This indicates that a species requirement is a specific form of restriction requirement focused on distinct embodiments within a single inventive concept.