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International Fuel Tax Agreement (IFTA) | Help
Help Yourself Online
How to use Secure Messaging in Your Revenue Online Account
Call Us With Your Tax Matters
IFTA Decals and Other Information:
Customer Service Representatives are available Monday through Friday, 8 a.m. to 4:30 p.m.
Other Contact Phone Numbers
EFT/Electronic Payment Help
Report Tax Evasion, Fraud or Scams
Hearing or Speech Impaired: Relay Colorado
To use this service, dial the appropriate number above. Give the Relay Colorado agent the number that you would like to call. The Relay Colorado agent will stay on the line to relay the information/conversation to you.
TTY Telephone Users: 1-800-659-2656
Voice Telephone Users: 1-800-659-3656
Assistance in Person
The following offices have staff available who:
Can assist with general information regarding taxes
Can provide tax account registration assistance
Can provide tax filing assistance
Perform enforcement and business seizure activities due to failure to file taxes, and monitor tax delinquencies.
See list of
Taxation Service Centers