1. (a) To obtain a copy of a previously filed Oklahoma income tax return, submit Form 599 to: Oklahoma Tax Commission Oklahoma City, OK 73194. Include the following information:

   1. (1) Tax year(s) requested;
   2. (2) Social Security Number (SSN) or Employer Identification Number (EIN);
   3. (3) For joint income tax returns, provide both SSNs or EINs.
2. (b) The copying fees are $5.00 per copy for each Oklahoma return. The fee for mailing by certified mail is $7.00. Full payment, made payable to the Oklahoma Tax Commission, must be included with the request. Enter the SSN or EIN and “Form 599 Request” on the check or money order.

Amended at 42 Ok Reg, Number 20, effective 7-15-25