Eighteen thousand eight hundred and thirty-three consecutive army inductees from the Tel Aviv and Central Districts in Israel were examined for hepatitis B surface antigen (HBsAG) by the counterelectrophoresis technique. The overall prevalence was 1.36%, with a higher rate for males (1.84%) than for females (0.78%). The highest rates were observed among Jews of North African and Yemenite origin (4.14 and 3.97%, respectively) and the lowest rates was found among Jews of European origin (0.31%). There was a negative correlation between the prevalence of HBsAg and the level of education. If we assume that the prevalence of HBsAg in a population reflects the rate of infection with hepatitis B virus interacting with host factors, the results of this study support the hypothesis that infections with type B hepatitis in Israel occur mainly during childhood, more frequently among the lower socioeconomic classes, and with a predilection of either the infection or of the chronic carrier state for males and certain ethnic groups.