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File an Appeal

To protest a notice of proposed audit adjustment or a refund denial, or any part thereof, a taxpayer must make a written application to the Executive Director of the Colorado Department of Revenue. This written application is a request for a formal hearing to present the facts, laws and arguments of the dispute. Taxpayers may also request an administrative hearing of a home rule jurisdiction’s assessment or denial of refund pursuant to Section C.R.S. 29-2-106.1 after exhausting their local remedies.


The written application (protest) through Revenue Online or on paper must be filed within thirty (30) days from the date of the notice or the refund denial or within thirty (30) days of exhaustion of local remedies.


Requests for a hearing pursuant to Section C.R.S. 29-2-106.1 must be submitted on paper, with a duplicate copy of such request for hearing filed contemporaneously with the applicable home rule jurisdiction. The 30-day period was created by statute and cannot be modified. If the protest is not filed within the 30-day period following the date of mailing of the notice or refund denial (not the date of receipt by the taxpayer), the Executive Director is required by law to make a final determination per Section C.R.S. 39-21-103. If the 30-day period ends on a Saturday, Sunday, or legal holiday, the protest will be due on the following business day.


The protest must contain at least the following information:


  • Taxpayer name and address
  • A reference number (may be account number or any other reference number noted on the notice or denial)
  • The taxable period(s) involved
  • The amount(s) and kind(s) of tax in dispute
  • An itemized schedule of the findings with which the taxpayer does not agree
  • A statement summarizing the reasons the taxpayer believes tax is not due or the refund denial is incorrect

A taxpayer may opt to submit their case to the Executive Director by written brief instead of in person at a formal administrative hearing as provided in Section C.R.S. 39-21-103(7).For each notice or refund denial that is being protested, a new protest must be filed. Each protest must be signed by the taxpayer and they must swear that the facts stated therein are true.Only the named individual taxpayer, general partner of a partnership, officer of a named corporation, or an individual authorized by such proper person's power of attorney may sign the protest. Applications improperly signed are invalid and will not be accepted. Failure to file a valid protest may deny the taxpayer valid standing in an appeal to the courts, and allow the Department to begin collection procedures. [Section C.R.S. 39-21-103 and C.R.S. 39-21-104.]The application for a hearing is made to the Executive Director; however, to speed handling, it should be mailed to the attention of the reviewer or the section whose name appears on the notice or refund denial.


The protest should be sent to the following address:


Colorado Department of Revenue
P.O. Box 17087
Denver, CO 80217-0087

All protests will be reviewed for any matters lacking factual information. Once factual matters are resolved and assuming the protest has not been resolved, the protest will be transmitted to the Tax Conferee Section. The Tax Conferee Section will then review disputed matters of law after the factual matters are resolved.


The taxpayer's written protest and the Department's documents supporting the notice or refund denial are reviewed by the Tax Conferee Section prior to the scheduling of any formal hearing. Suggested changes listed in the protest may be accepted or rejected based on their validity or applicability. An informal conference may be scheduled to discuss the protest and to allow the submitting of additional evidence in support of the protest. The informal conference does not waive any of the taxpayer's right to an administrative hearing. In the event the protest is not resolved by the Tax Conferee the protest will be forwarded to the Executive Director for formal hearing.