Despite long-standing public support for sex education in the schools, it has been difficult to show concrete effects of sex education on sexual and contraceptive behavior. Data from the 1988 National Survey of Family Growth indicate that exposure to a formal contraceptive education program increases the likelihood that a teenage woman will use a contraceptive method at first intercourse. According to the results of a multivariate analysis, the odds that a young woman will use any method and the odds that she will use a condom increase by about one-third following instruction about birth control; the effect on the likelihood of pill use, however, is nonsignificant. If contraceptive education occurs in the same year that a teenager becomes sexually active, the odds of any method use and of condom use are increased by 70-80%, and the odds of pill use are more than doubled. The results also suggest that with greater educational efforts, the proportion of teenagers who use condoms at first intercourse could increase from 52% to 59%, while the proportion using no method might decrease from 41% to 33%.