We surveyed the risk-taking behaviour of students aged 16 years and over in two New Zealand high schools, with a particular focus on road safety, substance use, sexual behaviour and personal safety. The questionnaire was completed by 471 students, a participation rate of 99 per cent. We found that seven out of 10 students who had ridden either a bicycle or motorcycle in the previous 12 months had not always worn a helmet; that 56 per cent had driven a car without a licence; and 23 per cent had been involved in a motor vehicle crash. A lifetime incidence of 63 per cent for cigarette smoking, 34 per cent for marijuana use and 78 per cent for alcohol use was found. Forty per cent of the students reported ever having sexual intercourse. During the previous 12 months, 49 per cent of these had not always used contraceptives and 61 per cent reported not always wearing condoms as protection for sexually transmitted diseases. Twenty-five per cent had physically harmed another person and 10 per cent reported carrying a weapon with the intent of harming someone else. This study shows that adolescents are willing to provide information on risk taking and that they are engaging in high levels of health-harming behaviour. Such information is important for designing health promotion programs to address adolescent risk taking.