objective: the objective of this study is to evaluate the efficacy of naltrexone with brief intervention among patients with alcohol dependence. method: this study is a 12-week randomized, double blind, placebo-controlled clinical trial. the sample of 71 patients was randomly divided in two groups (one receiving naltrexone and the other placebo). alcohol-dependent subjects were treated with 50 mg of naltrexone or placebo daily for 12 weeks. both treatment groups received brief intervention. the primary results for this study were relapse rate and change in drinking behaviors. results: in the intention-to-treat fewer naltrexone treated subjects relapsed (3% 21%; p = 0.054). naltrexone with brief intervention was not effective in decreasing drinking days (6.2 + 10.6 3.05 + 7.3; p = 0.478), moderate drinking days (0 2.2 + 6.9; p = 0.345) and heavy drinking days (0.03 + 0.2 0.3 + 0.9; p = 0.887). naltrexone was well tolerated. the most frequent adverse effects in our sample were: headache (25.4%), drowsiness (20.9%), nausea (16.4%), hyperphagia (16.4%), anorexia (14.9%), anxiety (10.4%), heartburn (10.4%) and irritability (10.4%). conclusions: although the naltrexone group showed a tendency to reduce relapse rate (> 5 drinks/day), no differences were found in other alcohol consumption variables between naltrexone and placebo groups. further studies should examine the efficacy of this kind of treatment combination in the primary health care.