Of 426 hospital staff tested for hepatitis B surface antibody (anti-HBS) by the radioimmunoassay method 57 (13.4%) had positive results. Laboratory staff had the highest prevalence, followed by nurses, and both values were significantly higher than that of administrative staff. Clerical staff working in laboratories were at the same risk for hepatitis B as general-duty nurses. Significantly more staff with anti-HBS had a history of hepatitis (19.3%) compared with staff without anti-HBS (79%), and significantly more staff with a history of hepatitis had anti-HBS (25.6%) compared with staff without such a history (12.0%). History of blood transfusions was not related to prevalence of anti-HBS. The risk for hepatitis B is greater in hospital staff who are in direct contact with patients or handle patients' blood and other specimens. However, contact with patients is less important than contact with patients' blood and other specimens.