We examined the association between substance abuse treatment services and emergency department (ED) utilization among participants in the HIV-Alcohol Longitudinal Cohort study of HIV-infected persons with a history of alcohol problems. A standardized questionnaire was administered to 350 subjects inquiring about demographics, substance use, use of substance abuse treatment services, and ED attendance. We operationally defined substance abuse treatment services as: stable, unstable, or none. The outcome, ED attendance, defined as presenting to an ED without subsequent hospitalization, occurred in 101 (28.8%) subjects in the past 6 months. Stable substance abuse treatment was significantly associated with lower odds of ED attendance (adjusted odds ratio; 95% CI): (0.5; 0.3-0.9). The relationship between substance abuse treatment and HIV-infected individuals' use of health care services merits additional attention. Substance abuse treatment may present an opportunity to impact health care utilization patterns of HIV-infected persons with a history of alcohol problems.