This study evaluated an integrated treatment for comorbid problem gambling, anger, and substance use. Problem gamblers with comorbid anger problems (N=42), half of whom also had substance use disorders, were randomized to either a 14-week integrated treatment targeting anger and addictions (i.e., both gambling and substance use) or a specialized treatment-as-usual (TAU) for gambling and substance use. Participants were assessed at baseline (Tl), 14 weeks (T2), and 12 weeks follow-up (T3). Relative to the TAU, participants in the integrated anger and addictions treatment reported significantly less gambling at T2 and T3 and less trait anger and substance use at T3. Findings suggest that it is important to screen gambling clients for the presence of comorbid anger and substance use problems and that, when present, these problems need to be addressed concurrently in gambling treatment in order to optimize treatment outcomes.