IMPORTANCE Intimate partner violence (IPV) and heavy drinking are co-occurring public health problems, but integrated brief interventions for these conditions have not been tested. OBJECTIVE To determine whether a brief motivational intervention provided at the time of an emergency department (ED) visit reduces IPV and heavy drinking. DESIGN, SETTING, AND PARTICIPANTS A randomized clinical trial conducted at 2 US academic urban EDs between January 2011 and December 2014 to assess the effectiveness of a motivational intervention for IPV-involved female ED patients (ages: 18-64 years; N = 600) who exceeded sex-specific safe drinking limits. All received social service referrals; 2: 2: 1 to brief intervention (n = 242), assessed control (n = 237), or no-contact control (n = 121). INTERVENTIONS A 20- to 30-minute manual-guided motivational intervention (recorded and monitored for fidelity) delivered by master's-level therapists with a follow-up telephone booster. The assessed control group received the same number of assessments as the brief intervention group; the no-contact control group was assessed only once at 3 months. MAIN OUTCOMES AND MEASURES Incidents of heavy drinking and experiencing IPV measured over prespecified, 12 weekly assessments using an interactive voice response system. RESULTS Of 600 participants, 80% were black women with a mean age of 32 years. Retention was 89% for 2 or more interactive voice response system calls. Seventy-eight percent of women completed the 3-month interview, 79% at 6 months, and 71% at 12 months. During the 12-week period following the brief motivational intervention, there were no significant differences between the intervention group and the assessed control group on weekly assessments for experiencing IPV (odds ratio [OR], 1.02; 95% CI, 0.98-1.06) or heavy drinking (OR, 0.99; 95% CI, 0.96-1.03). From baseline to 12 weeks, the number of women with any IPV in the past week decreased from 57%(134 of 237) in the intervention group to 43%(83 of 194) and from 63%(145 of 231) in the assessed control group to 41%(77 of 187) (absolute difference of 8%). From baseline to 12 weeks, the number of women with past week heavy drinking decreased from 51%(120 of 236) in the intervention group to 43%(83 of 194) and from 46%(107 of 231) in the assessed control group to 41%(77 of 187) (absolute difference of 3%). At 12 months, 43%(71 of 165) of the intervention group and 47%(78 of 165) of the assessed control group reported no IPV during the previous 3 months and 19% (29 of 152) of the intervention group and 24%(37 of 153) of the control group had reduced their alcohol consumption to sex-specific National Institute on Alcohol Abuse and Alcoholism safe drinking levels. CONCLUSIONS AND RELEVANCE For women experiencing IPV and heavy drinking, the use of a brief motivational intervention in the ED compared with assessed and no-contact controls did not significantly reduce the days of heavy drinking or incidents of IPV. These findings do not support a brief motivational intervention in this setting.