The prevalence of antiHA was assessed in 594 hospital employees and in control groups comprising 932 "healthy" adults not working in the hospital, selected from different socioeconomic classes. Age specific antiHA prevalence which was lower in doctors than in nurses and ancillary staff, was also found to be lower in each group than in the respective controls, matched according to socioeconomic criteria. It is concluded that in our population (i.e. high risk area) the hospital environment does not involve an increased risk of HAV infection for personnel. However, precautions should be taken when working in high risk department, as this study demonstrated that a considerable proportion of health care workers (above all doctors) are still susceptible to Hepatitis A virus infection.