OBJECTIVE:To determine rate of pregnancy and use of contraception in a nationally representative sample of school students. METHODS:Year 10 and 12 students from a representative random sample of schools throughout Australia completed a survey concerning health and sexual behaviour. RESULTS:Thirty-five per cent of students had experienced sexual intercourse. Of these, 6.1% (males 4.1%, females 7.8%) reported they had experienced sex that resulted in pregnancy, and a further 7.5% were unsure. Most sexually active students reported using a condom (65%), and a further 36.8% reported using the pill for contraception the last time they had sex. Relatively few students (17.2%) used a dual contraceptive (female method and condom). CONCLUSIONS:Rates of reported pregnancy among Year 10 and 12 students are relatively high. Although the majority of students used some form of contraception when they had sex, a significant minority practised unprotected and unsafe sex. IMPLICATIONS FOR PUBLIC HEALTH PRACTICE:Sex education concerning pregnancy and sexually transmitted infection risks must be delivered early enough to influence first and early sexual activity.