• state offices are closed Monday

    CDOR Offices Will Be Closed in Observance of Presidents' Day

    After the holiday, the Department will reopen on Tuesday, February 18th at 8:00 a.m. MT.

  • 2020 Form Changes: Sales Tax DR 0100


    The Retail Sales Tax Return (form DR 0100) has changed. Learn more. 

  • Learn how to Spot Tax Fraud

    Prevent Fraud This Tax Season

    Visit our NEW Fraud Prevention Mini-Site to learn how you can help prevent and report tax fraud. 

  • Link to information about TABOR refunds

    What do Coloradans need to know about TABOR this year?

    Learn more about the 2019 TABOR Refund. 

Top Tax Training Videos

How to Add a Non-Physical Site for Sales & Use Tax in Revenue Online

Revenue Online Log-In Troubleshooting - Browser Authentication

Taxation News

The 2020 Retail Sales Tax Return Form is Now Available

The DR 0100 has changed for the 2020 tax year. See what has changed...

Did You Know that 84% of Taxpayers Submit their Return Electronically? 

Learn how you can too by using Revenue Online, the Department's FREE tax filing and account management tool.

The 2019 Income Tax Best Practices Guide is Available

This tax season, review the 2019 Income Tax Best Practices Guide for filing tips. Visit the Tax Training web page for more information.

Sales Tax Non-Filer Notices

If you received a notice from the Department about not filing your sales tax return, you have a few options.

Did You Receive a Letter From Us? 

Review this FAQ to find out next steps.

Request a Payment Plan

Watch this video for information on how to request a payment plan. 

Do You Sell Products Online?

Learn more how online and other types of marketplaces impact your sales tax responsibilities. 

Alpha Index