A group of 1.085 students (582 M, 503 F) attending high school (742) and nursing school (343) filled in an anonymous questionnaire on their sexual habits and their knowledge of contraception and sexually transmitted diseases. Overall, 57% of the study population had already a complete sexual intercourse at a mean age of 16,4 (SD +/- 1,8). 74% had 1-3 sexual partners, whereas 28% had more than 3. All students affirmed that it was possible to prevent sexually transmitted diseases and 92,6% indicated correct methods. However 10% of students did not know that AIDS is transmitted sexually as 47% hepatitis B. The responses made by nursing students were more correct that those of high school students.