Pathological gambling shares many similarities to substance use disorders, including some diagnostic criteria and high rates of comorbidity. This chapter reviews epidemiological and treatment studies exploring the relationship between disordered gambling and substance use. It also delineates the increased problems experienced by individuals with both disorders. Further, this chapter describes treatment interventions for individuals with gambling problems. Existing research demonstrates the efficacy of cognitive-behavioral therapy for pathological gambling as well as motivational enhancement therapy for gambling behavior problems. Based on consideration of these findings, we suggest an integrated treatment approach to assist dually diagnosed clients in overcoming concurrent gambling and substance use problems. However, further empirical research is needed to evaluate the efficacy of treatments specifically for this dually diagnosis population.