During a 1-yr period (November 1985-86), a free-of-charge vaccination program against hepatitis B was offered to 809 of the 1200 medical workers in a 650-bed general and regional hospital in Israel. Three hundred and eighteen (39.3%) accepted the offer and were vaccinated. The higher rates of acceptance were among cleaning personnel (96.3%) and student nurses (63.9%). The lower rates of acceptance were among physicians (46.5%) and nurses (24.9%). Different types of fear, as well as lack of knowledge, were the reasons responsible for 73.3% of all refusals. More specific and continuous health educational efforts among high-risk groups should be initiated for voluntary vaccination programs in Israel.