Although bipolar disorder is the Axis I disorder associated with the highest risk of having a coexisting substance use disorder, no specific treatment approaches for this dually diagnosed patient population have thus far been developed. This paper describes a 20-session relapse prevention group therapy that the authors have developed for the treatment of patients with coexisting bipolar disorder and substance use disorder. The treatment uses an integrated approach by discussing topics that are relevant to both disorders and by highlighting common aspects of recovery from and relapse to each disorder.