If my roommate doesn't have a lease do I need an eviction notice and have to go through the eviction process to get him out?

Leases of real property for a term of one year or less need not be in writing to be enforceable. See C.R.S. §38-10-106.  You will need to evict your tenant if he will not leave by agreement. Please note this response is general in nature and is not legal advice. No attorney client relationship is formed by it. Further, the response does not represent the opinions or views of LexisNexis or its affiliated companies. I hope this helps. Kind regards,   Cyrus Rajabi