- Background Hepatitis B vaccine was introduced into the regular immunization schedule in Israel in 1992. At the time, a need for a catch-up vaccination for those aged 4–18 years, became apparent. Study objective To evaluate the vaccination rate for hepatitis B among children aged 4–18 years. Subjects The study population consisted of a national sample of 1500 children aged 4–18 years, registered at large family practices and pediatric centres, belonging to Clalit Health Services (Health Maintenance Organization). Design and setting A total of 817 telephone interviews were conducted with parents of the sampled children regarding hepatitis vaccination status and facilitating factors or barriers for vaccination. Results The overall percentage of the children vaccinated was 19%, with 14.8% receiving the full immunization course. The variables found to be significantly associated with being vaccinated were (p < 0.05): families with one to three children; first born; higher education level of parents; number of parents’ visits to the physician in the last 3 months, higher parents’ immunization status; and younger parents. The main reason for vaccination noted was a recommendation. Of those not immunized, 50% noted that the main reason was a lack of recommendation. Conclusions and Implications forpractice The outlined factors found to be associated with vaccination might benefit others facing vaccination catch-up programs and the central role the primary care physician has as a recommending factor. Careful planning is clearly needed in developing an effective catch-up program.