You need to send a notarized Form DR 5714 requesting the period of the return needed. It will take from seven to ten days to receive your copies.You can get copies of tax returns for the past nine years.
Cost:
$0.25 per Page (1st 10 pages free)
Address:
Colorado Department of Revenue
Tax Files,
Denver, CO 80261
Forms to Use:
DR 5714
References: