This study examined the association between approximate distance traveled to treatment, and treatment completion and length of stay, for 1,735 clients attending outpatient treatment in an urban area. Clients who traveled less than 1 mile were 50% more likely to complete treatment than clients who traveled more than 1 mile, after holding constant demographic variables and type of drug problem. Similarly, clients who traveled more than 4 miles were significantly more likely to have a shorter length of stay than clients who traveled less than 1 mile. These findings have important implications for the geographic placement of new treatment facilities, as well as the provision of transportation services to maximize treatment retention.