A cross sectional anonymously administered questionnaire was used amongst 1689 secondary school girls and boys to determine their knowledge of AIDS and other sexually transmitted diseases (STDs). Their knowledge was found to be very low. While 80% could name an STD in an open question, only 16% could recognise the important symptoms of the common and treatable diseases such as gonorrhoea and syphilis. This finding is worrying in view of the fact that these common STDs facilitate transmission of HIV/AIDS. The awareness of AIDs was high but when it came to the mode of transmission of AIDS the large majority were not aware of the risk of intercourse with an infected person. Furthermore, despite an intensive AIDS awareness campaign programme mounted by the government of Zimbabwe a large number of students thought that one can contract HIV/AIDS by shaking hands, sharing a toilet and witchcraft. Misconceptions on transmission abound. The data show that there is a need to review strategies of disseminating information to teenagers regarding STD, including AIDS, reproductive biology, sexuality and contraception. The best strategy may be the introduction of a reproductive health education curriculum in all schools starting at an early age.