Men who are violent toward their partners tend to have a dual problem with alcohol and drug use, yet little is known about differences between men with single rather than dual problems. This study was one of the first to evaluate differences between alcohol dependent men who were arrested for Intimate Partner Violence (IPV) with and without concurrent illicit drug use. Seventy-eight participants were randomly assigned to manual-guided group behavioral therapies (Cognitive Behavioral Therapy or Twelve Step Facilitation) and assessed across 12 weeks of treatment. Despite denying drug use at baseline, thirty-two clients (43%) tested positive for illicit drug use (cocaine and marijuana) during the 12 weeks of treatment. The study specifically addressed whether there were differences between clients using alcohol only versus individuals using both alcohol + drugs in terms of 1) baseline characteristics; 2) treatment compliance (e.g., attendance and substance use during treatment; and 3) treatment outcomes (alcohol, drug use, anger management, and aggression at the completion of treatment). The results showed that there were comparatively few differences between the alcohol versus the alcohol + drug using groups at baseline. Regarding treatment compliance and retention, alcohol + drug using participants attended significantly fewer sessions, had significantly fewer percent days abstinence from alcohol use, significantly more total days of positive breathalyzer results. Regarding treatment outcomes across anger management and aggression scores, the alcohol + drug using participants had significantly more impairments in anger management styles from pre- to post-treatment. However, there were no differences between the groups across verbal or physical aggression. Both groups improved in their verbal aggression from pre- to post-treatment. The findings suggest that alcohol dependent men who continue to use illicit drugs may require additional interventions to effectively control their drug use and, their anger management styles.