Project Objectives: This project is designed to test the effect of a CBT intervention for patients with chronic pain who are already engaged in VA treatment for substance use disorders compared to an educational supportive condition on measures of pain intensity, pain-related disability and pain-tolerance. A set of secondary analyses will examine if group CBT compared to the educational supportive condition is associated with greater reductions in illicit substance use over the follow-up time period and whether during-treatment reductions in pain mediate the effect of treatment assignment on later substance use. Finally, a series of secondary analyses will explore whether the hypothesized mechanisms of action for the CBT intervention mediate the effect of this intervention on pain intensity and pain tolerance.