To assess the extent to which US hospitals have established employee health services with infection control functions, we analyzed information obtained in the SENIC Project (Study on the Efficacy of Nosocomial Infection Control) from interviews with hospital officials and staff nurses in a representative sample of 433 hospitals. Sixty-eight percent of hospitals had a formal employee health service. The percentage routinely screening employees varied widely from the more common tests, such as the yearly chest roentgenogram (89%) and skin test (83%), to less common tests, including stool cultures (43%) and blood testing for hepatitis B (41%) and rubella (33%); 40% routinely obtained cultures of personnel. Although most hospitals appear to screen adequately, a sizeable minority either fail to employ recommended screening tests or continue unnecessary, expensive ones.