What are the four statutory categories of patent-eligible subject matter?

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 four statutory categories of patent-eligible subject matter, as defined in 35 U.S.C. 101, are:

• Processes
• Machines
• Manufactures
• Compositions of matter

As stated in the MPEP, “The latter three categories define ‘things’ or ‘products’ while the first category defines ‘actions’ (i.e., inventions that consist of a series of steps or acts to be performed).”