This study was realized with 2.684 students of the high school in Rio Branco¾Acre, Brazil, to verify aspects of the sexual activity and the occurrence of DST/AIDS. From the researched students, 48,9% had sexual intercourses, and the largest frequency was 34,3% for male sex, with the beginning at 13 years old, and for female sex 31,6%, with the beginning at 16 years old. The occurrence of mentioned DST/AIDS was: 58,4% for Hepatite B, 39,4% for Monilíase and 2,2% for Gonorrhea. Among those ones who had their first sexual intercourse, 47,6% were with the boyfriend, 25,8% with the neighbor and 10,5% with the domestic maid. Concluding, the students who had sexual intercourses were 52,3% of private schools, 50,0% of federal ones, 45,7% of state ones and 41,8% of municipal ones.
sex; sexually transmissible disease; sexual education; acquired immunodeficiency syndrome