The Colorado Department of Revenue (CDOR) has created a system called Revenue Online that is now the preferred method for communicating with the CDOR on most matters affecting your state withholding, sales, and income taxes. This system also allows you to pay most kinds of state taxes via electronic funds transfer (EFT). Additionally this system allows us to communicate with the CDOR on your behalf and to research history in your account. We highly recommend that you register for this service and give us the authority to access the account on your behalf. You can register and access this system at If you have not already registered please do so (see detailed instructions at our website by clicking here). If you have already registered, please add us as an allowed third party to access your account (see detailed instructions at our website by clicking here). Please contact Cassy at 223-0792 or for our login ID and to discuss the level of access required for your circumstance.