Hepatitis A is an important infectious disease in Israel. The high incidence of hepatitis A, the declining prevalence of antibodies against hepatitis A virus throughout the past decade, and the availability of an active immunization for hepatitis A have engendered the identification of occupations in which workers are at increased risk of acquiring the disease. A prevalence study for hepatitis A antibodies was conducted during the first half of 1998 in a random sample of 37 day-care centers in different parts of Israel. A short interview was conducted, and serum samples were then collected from each worker. The control group comprised a sample of factory workers, blood donors, and women in maternity wards. Ninety percent (402 of 446) of the day-care workers had antibodies to hepatitis A. In a logistic-regression analysis, seropositivity was associated with increased age, minimal education, and lack of military service. When the authors compared a subsample of workers aged 18-40 yr with the control group, seropositivity was associated with the following: birth in Israel, duration of residence in Israel, very minimal education, military service, and employment in a day-care center. These results, together with earlier reports, indicate that day-care workers are at high risk of occupational exposure to hepatitis A. These results may imply that seronegative workers have a 2-fold chance of acquiring hepatitis A. Appropriate preventive measures should be considered, and active immunization of susceptible workers should be undertaken.