What is an S-signature and how should it be used in USPTO correspondence?

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.

An S-signature is a type of electronic signature used in USPTO correspondence. According to MPEP 501, which cites 37 CFR 1.4(d)(2):

An S-signature is a signature inserted between forward slash marks, but not a handwritten signature as defined by paragraph (d)(1) of this section. An S-signature includes any signature made by electronic or mechanical means, and any other mode of making or applying a signature other than a handwritten signature.

Key requirements for an S-signature include:

• It must consist only of letters, Arabic numerals, or both, with appropriate punctuation.
• The signer must insert their own S-signature with a single forward slash mark before and after the signature.
• For patent practitioners, their registration number must be included with or near the S-signature.
• The signer’s name must be presented in printed or typed form near the S-signature.

Example of a proper S-signature: /John D. Smith/

S-signatures can be used for most USPTO correspondence filed electronically or by facsimile.

For more information on USPTO correspondence, visit: USPTO correspondence.