To evaluate the risk of human immunodeficiency virus (HIV) exposure among emergency department workers (EDWs) and their ability to identify HIV-infected patients, a seroprevalence study was performed in March 1991 in the emergency departments (EDs) of six Italian urban hospitals. At each visit, patients aged 18-65 years were asked to undergo fingerstick blood sampling for anonymous, unlinked HIV testing performed on blood adsorbed filter paper collection cards. Demographic characteristics, known or suspected HIV risk factors, and occupational exposures reported by the EDWs during the patient's visit were recorded. On 9,457 consecutive visits, 9,005 samples (95%) were tested and 65 (0.7%) were HIV positive. ED staff failed to identify 59% of HIV-infected patients. The rate of occupational exposures was 0.13/100 visits. As it is impossible to predict the HIV status of patients attending EDs, adherence to universal precautions and the development of safer devices should be utilized to minimize the risk of blood-borne infections in EDWs.