We examined the knowledge, attitudes and practices of Omani adolescents with regard to reproductive health in a nationally representative secondary school-based sample of 1670 boys and 1675 girls. Through a self-administrated questionnaire the adolescents were asked about puberty, marriage, birth spacing and AIDS and sexually transmitted infections. Only half of the sample knew the changes at puberty of their own sex, while even fewer knew the changes in the opposite sex. Girls were inclined significantly towards later age of marriage than boys. The mean number of children desired by the sample was 4.9. About two-thirds of the adolescents had a positive attitude toward modern contraceptive methods and intended to use them in the future. Knowledge of fertility period was poor as was knowledge of AIDS and sexually transmitted infections. There was a high rate of approval (80%) of female genital cutting by both sexes.