Occupational, epidemiologic, and attitudinal factors in hepatitis-B vaccine acceptance in health care workers were examined. A questionnaire was mailed to a stratified random sample of 1,018 health care workers at risk for occupational blood exposure at a hospital in Iowa; of these, 919 completed and returned the questionnaire. There were 21 workers who reported a history of hepatitis-B or prior natural immunity. Potential reasons for vaccine acceptance or refusal were evaluated with factor analysis. Fifty four percent of previously nonimmune workers had completed the series, while 70% had received one or more doses. Hepatitis-B vaccine acceptance was related strongly to social influence (physicians, supervisors, role models, friends, and spouse) and knowledge of the disease and vaccine, whereas refusal was primarily related to concern about vaccine side effects and problems with vaccine access. Independent predictors of initiating the vaccine series included younger age, occupation, increased blood exposure frequency, and increased frequency of recent influenza vaccination. Occupation (increased acceptance among housestaff, nurses, nursing assistants, laboratory technicians), increased frequency of blood exposure, and recent influenza vaccination also were predictors of series completion. The authors conclude that factors such as occupation and blood exposure frequency may help identify health care worker groups with low vaccine acceptance which are most likely to benefit from targeted vaccine delivery.