The Drug Abuse Reporting Program (DARP) was initiated in 1969 as a federally supported client reporting system for community-based drug abuse treatment programs. Posttreatment follow-up interviews were conducted with over 4,000 persons from 34 treatment agencies to describe major findings from the drug abuse treatment research of the DARP relating to treatment effectiveness and client functioning in the community. Results indicated that effective results had been attained by treatments such as methadone maintenance and therapeutic community and outpatient drug-free programs. Both performance during treatment and length of time spent in treatment were positively related to outcome. The data from the replicated studies and the overall consistency of DARP findings demonstrate the strong connection between treatment and posttreatment outcomes. (JAC)