A survey was conducted to examine high‐risk sexual behavior in a large group of adolescents who were involved with the juvenile justice system. The findings showed that these youth are at high risk for unintended pregnancy and AIDS and other sexually transmitted diseases. Compared to national norms, the sample reported a very early mean age at first intercourse and a high rate of pregnancy. Those who had been involved in a pregnancy reported having begun sexual activity the earliest of those surveyed. Most participants reported an extremely unreliable use of birth control, with this unreliable use of birth control being strongly associated with espousal of high‐risk attitudes but generally unassociated with factual knowledge regarding pregnancy and contraception. These findings support the argument for expanding the scope of traditional sex education and beginning sexuality education programs earlier than they usually are in this country.