The Department of Revenue is processing 2023 income tax returns. For more information, please read the Department's announcement.


File a Protest


Disputes Regarding State & State Collected Tax

To protest a notice of deficiency or rejection of refund claim, or any part thereof, a taxpayer must make a timely 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. The written application (protest) through Revenue Online or on paper must be filed within thirty (30) days from the mailing date of the notice of deficiency or the notice of rejection of refund claim.

If the protest is not filed within the 30-day period of the mailing date of the notice of deficiency or rejection of refund claim (note: this is not the date of receipt by the taxpayer), the Executive Director is required by law to make a final determination per §39-21-103(8), C.R.S. If the 30-day period ends on a Saturday, Sunday, or legal holiday, the protest will be due on the following business day. The 30-day period is a statutory requirement and cannot be modified or extended.

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 §39-21-103(7), C.R.S. For each notice of deficiency or notice of rejection of refund claim 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. Sections §39-21-103 and §39-21-104, C.R.S. The application for a hearing is made to the Executive Director, however, it should be mailed to the attention of the reviewer or the section whose name and address appear on the notice of deficiency or rejection of refund claim.

All protests will first be reviewed by the originating section for factual matters. If the review of factual matters does not resolve the protest, the originating section will forward the protest to the Tax Conferee Section. The Tax Conferee Section may address any remaining factual matters and will then review disputed matters of law.

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Disputes Regarding Home Rule & Self Collecting Jurisdictions' Tax

The Colorado Department of Revenue (CDOR) also provides dispute resolution for home rule jurisdictions' sales and use tax assessments or refund denials. Section §29-2-106.1, C.R.S. Taxpayers must first exhaust their administrative remedies with the local jurisdiction. Within 30 days of exhausting their local remedies taxpayers may request that CDOR hold an administrative hearing regarding a home rule jurisdiction's assessment or denial of refund. Taxpayers must submit a request for hearing pursuant to Section §29-2-106.1, C.R.S. within 30 days of exhausting their local remedies.

These requests for a hearing must be submitted on paper, with a duplicate copy of such request for hearing filed contemporaneously with the applicable home rule jurisdiction(s). The protest should contain the information listed above. Additionally the taxpayer should provide a copy of the home rule jurisdiction's notice of assessment or refund denial and copy of the hearing officer's decision, if a decision was issued by the local jurisdiction.

Requests for hearing of home rule disputes should be mailed to:

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