This article reports the results of an interview survey with 1,665 residents of Metropolitan Santiago 15-24 years old. The survey, which dealt with various aspects of reproductive health, indicated that the sex education received by 75% of the subjects generally failed to convey an accurate knowledge of the basic concepts of sexuality; that use of contraceptive methods was very limited; that approximately 25% of the 865 women interviewed had been pregnant at some time; and that 40% of all the pregnancies were unplanned. These findings demonstrate a need to begin effective sex education programs and to provide adolescent services commensurate with the circumstances of modern life.