Aims. To evaluate the efficacy of acamprosate in maintaining abstinence in weaned acohol-dependent patients. Design. A multicentre, double-blind, randomized control trial. Patients were individually randomly allocated to active or placebo conditions. Abstinence was assessed during a 6-month treatment period and after a 6-month follow-up period. Setting. A community-based, outpatient alcohol rehabilitation programme. Participants. Two hundred and forty-six alcohol-dependent patients between the ages of 18 and 65 years were recruited immediately following acute, inpatient withdrawal treatment. Measurements. The primary outcome measure was self-reported abstinence from alcohol since the previous sessions at 3, 6, 9 and 12 months following the start of treatment, with treatment taking place for a period of 6 months. Findings. A significantly higher proportion of patients in the acamprosate group were abstinent after 3 months and 6 months of treatment. The percentage of patterns with continuous abstinence at the end of the treatment period was almost double for the acamprosate group than for the placebo group (40.7% vs. 20.8%, respectively). Acarnprosate significantly increased the retention of patients in the treatment programme. Six months after drug treatment ceased, the criterion of abstinence since the previous visit was reached by significantly more patients from the acamprosate group (43.4%) than from the placebo group (29,8%), but Ms difference was not statistically significant at the 3-month point after cessation of study medication. Conclusions. Acamprosate may be a useful pharmacological compound for the long-term treatment of alcohol-dependence when applied in a community-based rehabilitation programme.