The sample consisted of injecting heroin addicts admitted between April 1990 and January 1993 to public methadone treatment programs in Corpus Christi, Dallas, and Houston. These clients were admitted to treatment as part of the Drug Abuse Treatment for AIDS-Risk Reduction Project funded to improve treatment retention, reduce drug abuse relapse rates, and improve the psychosocial adjustment of injecting drug users through enhanced intervention strategies. As expected, clients meeting DSM-III-R criteria were significantly more likely to show evidence of psychological problems and dysfunction in family and peer relations at admission. An unexpected finding was that these clients were also more likely to remain in treatment longer than drinking clients who did not report dependency. Alcohol dependent clients were significantly more likely to have poor experiences with self-help groups, which may have reflected less denial and relatively better ability to focus in opiate dependency problems. The authors conclude that failure to differentiate between alcohol dependent and nondependent groups of drinkers enrolled in methadone treatment may partially account for reported differences in treatment outcome studies and may help clinicians plan more effective treatment approaches. 33 references and 1 tables