Notice to offerors
How and by when receipt is acknowledged, and how an offeror who wishes to change an offer because of the amendment refers to it.
OF309
Amendment of Solicitation (Negotiated Procurements)
- Agency
- GSA
- Revision
- Rev. 9/1997
- Fillable fields
- 19
- Pages
- 1
- Official source
- GSA form page
- Checked
- October 20, 2026
Optional Form 309 (OF 309): Amendment of Solicitation (Negotiated Procurements)
Optional Form 309 (OF 309), Amendment of Solicitation (Negotiated Procurements), is a one-page form. Its footer reads OPTIONAL FORM 309 (9-97), Prescribed by GSA - FAR (48 CFR) 53.215-1(g), and it is marked authorized for local reproduction. GSA hosts it in its forms library.
Section I, Amendment, identifies the solicitation and the amendment, the office that issued it, any new due date, a contact for information and a description of the amendment. Section II, Acknowledgment of Amendment, is for the offeror, who may complete Blocks 9 and 10 and return the form to the address in Block 5.
A notice at the top says offerors must acknowledge receipt of the amendment in writing by the date and time specified for proposal submissions or the date and time in Block 6, whichever is later. You can fill it out free in your browser on this page and download the result without an account.
What's on OF 309
Blocks 1 to 4: identification
Solicitation number, solicitation date, amendment number and amendment date.
Blocks 5 and 6: issuer and due date
Issued by, and a due date with a date and a time. The form says the amendment does not change the date by which offers are due unless a date and time is inserted.
Block 7: information call
Name, area code and phone number, and e-mail address of the contact. The block says No collect calls.
Block 8: description of amendment
A large box for the change, followed by the line that, except as provided herein, all terms and conditions of the solicitation remain unchanged and in full force and effect.
Blocks 9 and 10: acknowledgment
Name and address of offeror, then the signature of the person authorized to sign, name of signer, title of signer and date.
How to complete OF 309
- 1
Identify the solicitation and amendment
Enter the solicitation number and date, the amendment number and the amendment date in Blocks 1 to 4.
- 2
Name the issuer and any new due date
Fill in Block 5. The form says the due date for offers stays the same unless a date and time is inserted in Block 6.
- 3
Give a contact and describe the change
Enter the contact's name, telephone and e-mail address in Block 7 and the description of the amendment in Block 8.
- 4
Acknowledge receipt
The offeror may complete Block 9 and sign Block 10, with name, title and date, instead of another written acknowledgment.
- 5
Return it to Block 5
The form says to return the amendment to the address in Block 5. The notice says an acknowledgment not received at the designated location by the specified date and time may lead to the offer being rejected.
These steps follow the notice and the blocks in order.
Why fill Form OF309 on indox
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Where it goes and what the form says
Where it goes
The signed acknowledgment returns to the address in Block 5, Issued by. The form prints no address of its own.
Timing stated on the form
The notice says receipt is acknowledged in writing by the date and time specified for proposal submissions or the date and time in Block 6, whichever is later.
Changing an offer
The notice says a change to an offer because of the amendment must reference the solicitation and the amendment and be received prior to the date and time in Block 6.
Regulation and reproduction
The footer reads Prescribed by GSA - FAR (48 CFR) 53.215-1(g) and AUTHORIZED FOR LOCAL REPRODUCTION. GSA's page lists 09/1997 as the current revision date.
What the PDF does not print
The PDF prints no fee, OMB number, burden estimate or privacy statement.
Related forms
Who fills out OF 309?
The form prints no separate instructions. Its notice and blocks show which part belongs to the issuing office and which to the offeror.
Official sources and the blank
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Questions about Form OF309
What is OF 309?
It is the Amendment of Solicitation (Negotiated Procurements) form, with Section I, Amendment, and Section II, Acknowledgment of Amendment.
Who issues OF 309?
The footer reads OPTIONAL FORM 309 (9-97), Prescribed by GSA - FAR (48 CFR) 53.215-1(g). GSA hosts a copy in its forms library.
How is receipt of the amendment acknowledged?
The notice says in writing. The form says that in lieu of other written methods, the offeror may complete Blocks 9 and 10 and return the amendment to the address in Block 5.
Does OF 309 change the date offers are due?
The form says the amendment does not change the date by which offers are due unless a date and time is inserted in Block 6.
What if the acknowledgment arrives late?
The notice says that if the acknowledgment is not received at the designated location by the specified date and time, the offer may be rejected.
Does the amendment change the rest of the solicitation?
The form says that, except as provided herein, all terms and conditions of the solicitation remain unchanged and in full force and effect.