As part of a countrywide program of tuberculin testing of 7th graders, 10,133 children were examined in the Tel Aviv area over the 3-year period, Septemer 1991-June 1994. Of these, 655 were from families recently arrived from the former Soviet Union (I), and 9478 from long-time resident families of Israel (L). Of the I group 537 had received BCG at least once (82.0%), of the L group 5306 (56.0%). In the nonvaccinated I group 33.9% had reactions of 10 mm or more (clinically significant) while the rate was 6.1% in the L group, a statistically highly significant difference. In the vaccinated I group the rate of clinically significant reactions was 49.3% as compared to 10.3% in the L group, also statistically a highly significant difference. In general, the clinically significant reactions were more commonly found in the I group as opposed to the L group. Both BCG vaccination and prior place of residence appear to be statistically significant independent variables. No cases of tuberculosis occurred among the entire population tested. These data provide a base for surveillance of tuberculosis risk in Tel Aviv specifically and Israel in general.