This study examined the Community Reinforcement Approach's (CRA) effect on AIDS risk behaviors and the relationship between comorbid psychiatric disorders and the risk for AIDS behavior in opioid dependent patients entering methadone maintenance treatment. Additionally, we looked at AIDS risk behaviors as they related to the Addition Severity Index (ASI), Beck Depression Inventory, Symptom Checklist-90-Revised (SCL-90-R), and the Social Adjustment Scale-Self Report (SAS-SR). Subjects (N = 227) were drawn from a large clinical trial that examined the effectiveness of a Community Reinforcement Approach for treatment of opioid dependence. Both CRA and standard treatment demonstrated a significant effect on reduction of AIDS risk behaviors. There was no relationship found regarding comorbid psychiatric disorders with the risk for AIDS behavior. However, there were correlations with other psychiatric, social, and substance abuse variables. Multivariate analyses indicated that increased drug and legal ASI composite scores were the primary predictors of increased AIDS risk behavior.