37 CFR 1.4 Nature of correspondence and signature requirements were established on September 21, 2004, by the United States Patent and Trademark Office (USPTO) to permit electronic or mechanical signatures, also known as "S-signatures" on any papers filed at the USPTO.

Determining What Comprises a Correspondence

Correspondence with the Patent and Trademark Office consists of the following:

  • Correspondence relating to services and facilities of the Office, such as general inquiries, requests for publications supplied by the Office, orders for printed copies of patents, orders for copies of records, transmission of assignments for recording, and the like, and
  • Correspondence in and relating to a particular application or other proceedings in the Office. See particularly the rules relating to the filing, processing, or other proceedings of national applications in subpart B of this part; of international applications in subpart C of this part; of ex parte reexamination of patents in subpart D of this part; of supplemental examination of patents in subpart E of this part; of extension of patent term in subpart F of this part; of inter partes reexamination of patents in subpart H of this part; of international design applications in subpart I of this part; and of the Patent Trial and Appeal Board in parts 41 and 42 of this chapter.

What are S-signatures?

An S-signature is:

  • a signature that is not handwritten and placed between forward slash marks
  • covers any signature created from electronic, mechanical, or other means other than handwritten
  • accepted on paper, facsimile transmission, or via the electronic filing system as an attachment

Examples of where S-signatures are allowed would include patent applications, patents, or a reexamination or supplemental examination proceeding.

Requirements of S-signatures

"The S-signature must consist only of letters, or Arabic numerals, or both, with appropriate spaces and commas, periods, apostrophes, or hyphens for punctuation, and the person signing the correspondence must insert his or her own S-signature with a first single forward slash mark before, and a second single forward slash mark after, the S-signature (e.g., /Dr. James T. Jones, Jr./); and (ii) A patent practitioner (§ 1.32(a)(1) ), signing pursuant to §§ 1.33(b)(1) or 1.33(b)(2), must supply his/her registration number either as part of the S-signature, or immediately below or adjacent to the S-signature. The number (#) character may be used only as part of the S-signature when appearing before a practitioner's registration number; otherwise, the number character may not be used in an S-signature."

The signer must also meet the following requirements:

  • printed or typed signature that is immediately below or adjacent to the S-signature
  • the identity of the signer is reasonably identifiable

When submitting an electronically submitted correspondence to the USPTO, the documents may be signed with a graphic representation of a handwritten signature or a graphic representation of an S-signature. It is also presumed that the signature that shows was entered by the person listed on the document. If this is found to be false, sanctions will be put forth and the authenticity of the form will be in question.

One exception to this rule is if a lawyer has been authorized to sign for their client. In regards to the USPTO, the lawyer's signature is deemed a solemn act and fully represents their word, certification, and promise and certifies the truthfulness of the contents of the document.

In some instances, the USPTO will require confirmation or evidence to authenticate the signature. This is typically triggered if there are variations of a signature or if the typed or printed name doesn't clearly identify the person signing the document.

Examples of S-signature

Three examples of S-signatures and how they should be formatted are shown here:

Example 1 – An S-signature for a pro se applicant Respectfully submitted,

/John Doe/
John Doe

Example 2 – An S-signature for a registered practitioner

Respectfully submitted,

By: /John Doe/
John Doe
Reg. No. 13579


Example 3 – An S-signature for a registered practitioner

Respectfully submitted,

By: /John Doe, #13579/
John Doe


The current and past USTPO interpretations of the slashes dictate that:

  • The slashes are required but not part of the S-signatures.
  • The slashes may be inserted prior to the signature being placed.
  • Document signing services, like Docusign, can be part of the workflow of electronic signatures.

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