Background: There is increasing interest in naltrexone, an opiate antagonist, in the treatment of opiate addicts. The effects of naltrexone are often compromised by a lack of compliance and drop-out. The effects of this compound are probably more favorable when combined with a psychosocial intervention such as the Community Reinforcement Approach (CRA). Aim: To explore the effects of a combination therapy (naltrexone plus CRA treatment) and the predictive value of sociodemographic and psychopathologic characteristics. Method: Using a before-and-after design, heroine addicts (n = 24) receiving a combined naltrexone plus CRA treatment are compared with a group (n = 20) on methadone maintenance therapy (reference group). Results: Over a period of 6 months, 58% (14/24) did not relapse, after 1 year at least 55% (12/22) still met the initial goal of continuous abstinence. At baseline, the treatment group and the reference group were similar on nearly all variables except for the number of times clients were arrested. Within the treatment group, a comparison was made between the continuous abstinent and those who relapsed into frequent opioid use. Differences were significant in the cluster-B personality disorders and in polydrug users. Conclusion: The combination of naltrexone plus intensive CRA in an outpatient setting appears to be promising. A high score on cluster-B and polydrug use is associated with relapse. Copyright © 2003 S. Karger AG, Basel.