The close link between alcohol and other drug abuse and STD morbidity and the positive impact of AOD intervention services in reducing STD morbidity, led the New York State Office of Alcoholism and Substance Abuse Services (OASAS) and the New York City Bureau of STD Control (BSTDC) to assess the prevalence of AOD problems among STD clinic patients. Assessing problematic AOD involvement among STD patients was of interest to BSTDC for STD prevention and to OASAS, for new AOD case-finding and early intervention. During fall, 2000, 100 STD patients in each of the 7 full-time BSTDC clinics in New York City were solicited in clinic waiting rooms; eligible patients were screened individually and anonymously with a modified CAGE-A (mCA). The mCA asks 4 questions about problematic AOD use "ever" (i.e., "lifetime") and currently (i.e., "in the past 30 days) rather than "in the past 12 months" of the CAGE and uses two or more "Yes" answers as a "positive" screen. The mCA also asks for age, sex, ethnicity, prior AOD treatment, and interest in an AOD referral. Only 2 of 704 eligible patients refused mCA screening, n = 702. Sixty percent were male, 87.7% Black and/or Hispanic, and 69%,