Colorado Form DR 1778 - e-filer Attachment Instructions

This form is to be used by electronic filers for submitting documents that would have otherwise been attached to a paper return. Some tax preparation software packages allow the document(s) to be added to the e-filed return as a PDF attachment, which will speed processing of the return. If the tax software does not include the option of attaching PDF documents, mail (do not email) the DR 1778 to:

Colorado Department of Revenue
1375 Sherman Street
Denver, CO 80261-0006

Questions? Go to or call the Department at (303) 238-7378