FillingPDF
Log in

Form PTO/SB/21, Transmittal Form

FillingPDF is not affiliated with, endorsed by, or connected to the U.S. Patent and Trademark Office (USPTO). Get the official form from the U.S. Patent and Trademark Office (USPTO) website.

Form PTO/SB/21, Transmittal Form

PTO/SB/21, the Transmittal Form from the U.S. Patent and Trademark Office (USPTO), accompanies patent correspondence sent after initial filing. Fill it out online on FillingPDF and download or print the completed PDF.
2 pages
Page 1 of 2
Page 2 of 2
Click a highlighted field to fill it in. Your data is deleted after 7 days.

Form PTO/SB/21, Transmittal Form, is the U.S. Patent and Trademark Office (USPTO) form that identifies a patent application and lists the papers you send with a submission made after the application was first filed. You enter the application data, check every enclosure that applies, sign, and complete the certificate of transmission or mailing if you use it. It is one of several USPTO transmittal forms, so confirm that this is the one that fits your submission. On FillingPDF you can fill out the form online and download or print the completed PDF; the original PDF is published by the USPTO on its patent forms page.

Last updated

What is PTO/SB/21?

Form PTO/SB/21, Transmittal Form, is the U.S. Patent and Trademark Office (USPTO) form that accompanies correspondence sent after a patent application's initial filing, identifying the application and listing the papers enclosed with the submission.

The form is printed with the document code TRAN.LET and the document description "Transmittal Letter". Its top block records the application number, filing date, first named inventor, art unit, examiner name, attorney docket number and the total number of pages in the submission. An ENCLOSURES section with check boxes covers items such as an amendment or reply, an information disclosure statement, a terminal disclaimer, a power of attorney or change of correspondence address, fee papers, appeal communications and a request for refund. Space is left for other enclosures, CDs and remarks. The bottom of the form carries a signature block for the applicant, attorney or agent and a certificate of transmission or mailing.

The form carries OMB control number 0651-0031 and shows approval through 11/30/2027. The USPTO explains that an expiration date printed on its forms comes from the Paperwork Reduction Act approval process and does not mean the form is invalid after that date.

The USPTO lists Form PTO/SB/21 among its transmittals and cover sheets, next to separate application transmittals such as AIA/15, AIA/18 and AIA/19, the request for continued examination transmittal SB/30 and the reexamination transmittal SB/57. Those serve their own purposes; this form is the general transmittal for later correspondence. The USPTO also states that in almost all situations it does not require the use of a form, and that a submission meeting the Patent Laws and Rules will be accepted whether or not it resembles a USPTO form.

Who needs to file PTO/SB/21?

Applicants, attorneys and agents who are sending papers in a patent application that is already on file use Form PTO/SB/21. The form states that it is to be used for all correspondence after initial filing, and it is signed by the applicant, attorney or agent, with a registration number where one applies.

Conditions to keep in mind:

  • The USPTO's forms page says the forms listed on it are for patent applications filed on or after September 16, 2012. Forms for applications filed before that date are kept on a separate page.
  • The USPTO prohibits using its forms for purposes they were not designed for.
  • Use of the form is a convenience: the USPTO says that in almost all situations it does not require a form, and a submission that meets all requirements of the Patent Laws and Rules is accepted whether or not it is similar to a USPTO form.

This form is not the filing document for a new application. The USPTO publishes separate transmittals and cover sheets for that purpose, and for requests such as continued examination, reexamination and supplemental examination.

When to file PTO/SB/21

Use Form PTO/SB/21 whenever you send correspondence in a patent application after its initial filing. The form sets no deadline of its own: it travels with the paper you enclose, so the due date is whatever applies to that paper, such as a reply, a petition or an appeal communication.

If you complete the certificate of transmission or mailing at the bottom of the form, the date you enter is the date the correspondence is faxed to the USPTO or deposited with the United States Postal Service as first class mail, as the certificate wording states. The OMB approval date printed at the top does not limit when the form can be used.

Documents you need

  • The papers you check under ENCLOSURES: the form lists them and you send each one with it, for example an amendment or reply, an information disclosure statement or a petition.

How to fill out PTO/SB/21

  1. Identify the application

    Enter the Application Number, Filing Date and First Named Inventor in the top block.

  2. Add examination details

    Enter the Art Unit, Examiner Name and Attorney Docket Number for the application.

  3. Enter the total page count

    In Total Number of Pages in This Submission, enter the number of pages you are sending.

  4. Check application papers enclosed

    Under ENCLOSURES (Check all that apply), check each paper you send, such as Amendment/Reply, After Final, Affidavits/declaration(s), Information Disclosure Statement, Certified Copy of Priority Document(s), Drawing(s) or Terminal Disclaimer.

  5. Check fee, petition and appeal items

    Check boxes such as Fee Transmittal Form, Fee Attached, Extension of Time Request, Petition, Request for Refund, Power of Attorney, Revocation, Change of Correspondence Address, and the appeal communications that apply.

  6. Check missing-parts replies

    If you are replying to a notice, check Reply to Missing Parts/Incomplete Application, or Reply to Missing Parts under 37 CFR 1.52 or 1.53.

  7. Describe other enclosures and remarks

    Identify anything else under Other Enclosure(s) (please identify below). If you send a CD, enter the Number of CD(s) and check Landscape Table on CD where it applies, and add any note under Remarks.

  8. Complete the signature block

    Enter the Firm Name, then sign and print the name of the applicant, attorney or agent, with the Date and Reg. No.

  9. Complete the certificate if used

    In the Certificate of Transmission/Mailing, add the signature, date and typed or printed name of the person certifying the fax transmission or mailing.

  10. Review and download the PDF

    Check that the application data match your records and that every enclosure you are sending is checked. Download or print the completed PDF from FillingPDF and send it as described under How to submit.

How to submit PTO/SB/21

The printed form names mail as its submission address, mentions fax in its certificate of transmission, and the USPTO also operates the Patent Center electronic system for patent filings.

  • By mail: send the completed form with its enclosures to Commissioner for Patents, P.O. Box 1450, Alexandria, VA 22313-1450. The certificate on the form refers to first class mail with sufficient postage in an envelope addressed to the same Commissioner for Patents.
  • By fax: the certificate covers correspondence that is facsimile transmitted to the USPTO; the form prints no fax number.
  • Electronically: Patent Center is at https://patentcenter.uspto.gov/. For help with patent e-filing, call the Patent Electronic Business Center at 866-217-9197 or 571-272-4100, or email [email protected], Monday to Friday, 9:00 AM to 8:00 PM EST.

Comments about the form's burden estimate go to the Chief Administrative Officer, USPTO, P.O. Box 1450, Alexandria, VA 22313-1450 or [email protected]; the form says not to send fees or completed forms for that purpose. For help completing the form, call 1-800-PTO-9199 and select option 2. FillingPDF lets you fill out and download the PDF; submission follows the channels above.

Common mistakes to avoid

  • Using Form PTO/SB/21 for an initial filing; the form says it is to be used for all correspondence after initial filing.
  • Using the form for a purpose it was not designed for, which the USPTO prohibits.
  • Checking only some of the boxes under ENCLOSURES when more apply; the form says to check all that apply.
  • Checking Other Enclosure(s) without identifying the paper in the space provided below it.
  • Changing the wording of the certificate of transmission or mailing while leaving the text that identifies the form as a USPTO form; the USPTO says certification statements may not be changed.
  • Leaving the date blank in the certificate, which certifies the transmission or mailing on the date shown.
  • Sending a completed form to the address for burden-estimate comments instead of to Commissioner for Patents, P.O. Box 1450, Alexandria, VA 22313-1450.
  • Treating the approval date at the top of the form as an expiry after which it cannot be used; the USPTO says it does not make the form invalid.
  • Using it for an application filed before September 16, 2012; the USPTO keeps separate forms for those.

Frequently asked questions

What is Form PTO/SB/21 used for?

Form PTO/SB/21, Transmittal Form, is the USPTO form that accompanies patent correspondence sent after initial filing. It identifies the application and, through check boxes, lists the papers enclosed, such as replies, petitions, fee papers or appeal communications.

Do I have to use the USPTO transmittal form?

No. The USPTO says that in almost all situations it does not require a form. A submission that meets all requirements of the Patent Laws, Rules and USPTO notices is accepted whether or not it resembles a USPTO form, though the form can serve as a guide.

Can I fill out the transmittal form online?

Yes. You can fill out the fillable PDF online on FillingPDF and download or print it. FillingPDF does not file anything with the USPTO; you send the completed form by mail, by fax or through the USPTO's electronic channels.

Where do I mail Form PTO/SB/21?

Mail it to Commissioner for Patents, P.O. Box 1450, Alexandria, VA 22313-1450. The form directs completed forms there. For help completing it, call 1-800-PTO-9199 and select option 2.

What is the certificate of transmission or mailing on this form?

It is a block at the bottom where you certify that the correspondence is being faxed to the USPTO or deposited with the U.S. Postal Service as first class mail addressed to Commissioner for Patents, on the date you enter, with a signature and typed or printed name.

Does the expiration date at the top make the form invalid?

No. The USPTO says the date at the top right of its forms is part of the Paperwork Reduction Act approval process and does not indicate a date beyond which the forms are invalid. This form is printed with approval through 11/30/2027.

Can I use it for an application filed before September 16, 2012?

The USPTO's forms page lists this form among forms for applications filed on or after September 16, 2012, and keeps forms for earlier applications on a separate page. Check that page before using it for an older application.

Who signs Form PTO/SB/21?

The signature block is labeled for the applicant, attorney or agent. It has fields for the firm name, signature, printed name, date and registration number.

Ready to fill out PTO/SB/21?

Fill out PTO/SB/21 now