ABSTRACT: The efficacy of batterer intervention programs to reduce intimate partner violence (IPV) is questionable, with individuals with alcohol problems particularly unlikely to benefit. We examined whether adding adjunctive alcohol intervention to batterer intervention reduced the likelihood of substance use and violence relative to batterer intervention alone.Randomized clinical trial.Batterer intervention programs in Rhode Island, USA.A total of 252 hazardous drinking men in batterer intervention programs. Participants were randomized to receive 40 hours of standard batterer program (SBP) or the SBP plus a 90-minute alcohol intervention (SBP?+?BAI). None withdrew due to adverse effects. Data were collected at baseline, 3-, 6- and 12-month follow-up, with follow-up rates of 95, 89 and 82%, respectively.Substance use was measured with a well-validated calendar-assisted interview. Violence was measured with a validated questionnaire. Arrest records were obtained for all participants. The primary substance use outcome was drinks per drinking day (DPDD) and the primary violence outcome was frequency of any physical IPV.Relative to SBP alone, men receiving SBP?+?BAI reported consuming fewer DPDD at 3-month follow-up [B?=?-1.36, 95% confidence interval (CI):?-2.65, -0.04, P?=?0.04] but not 6- or 12-month follow-up. In secondary analyses, men receiving SBP?+?BAI reported significantly greater abstinence at 3- (B?=?0.09, 95% CI:?0.03, 0.14, P?=?0.002) and 6-month (B?=?0.06, 95% CI:?0.01, 0.11, P?=?0.01) follow-up but not 12-month follow-up. There were no significant differences in physical IPV between men receiving SBP and men receiving SBP?+?BAI. In secondary analyses, men receiving SBP?+?BAI reported less severe physical aggression at 3-month (IRR?=?0.18, 95% CI:?0.05, 0.65, P?=?0.009) but not 6- or 12-month follow-up. Men receiving SBP?+?BAI reported less severe psychological aggression (B?=?-1.24, 95% CI:?-2.47, -0.02, P?=?0.04) and fewer injuries to partners at 3- and 6-month follow-up (IRR?=?0.33, 95% CI:?0.12, 0.92, P?=?0.03), with differences fading by 12 months.Men with a history of intimate partner violence and hazardous drinking who received a batterer intervention plus an alcohol intervention showed improved alcohol and violence outcomes initially, but improvements faded by 12 months.