Positive, abstinence-oriented, social support is associated with good substance abuse treatment outcome but few interventions are designed to help patients improve their social supports. This article reports on a behavioral intervention designed to encourage opioid-dependent patients receiving methadone to include drug-free family members or friends in treatment and to use these individuals to facilitate development of a supportive, non-drug-using social network. This report uses data from a quality assurance program review of the treatment response of 59 opioid-dependent outpatients who identified a drug-free significant other to participate in their treatment. Fifty-five (93.2%) brought a significant other (most often the patient's mother, 29%) to both the initial evaluation session and at least one joint session. Social support activities were family- (33%), church- (28%), and self-help group-related (30%). Approximately 78% of patients who participated in the social support intervention achieved at least four consecutive weeks of abstinence. Women responded better than men. We conclude that methadone-maintained patients can and will include non-drug-using family members and friends in treatment, and these individuals can be mobilized to help patients improve their recovery.