A questionnaire measuring smoking status, exercise and dietary behaviour was administered to 932 high school pupils during regular classroom periods. Pupils were taken from three year groups which included 327 year 8 (12-13 years), 313 year 9 (13-14 years) and 292 year 10 (14-15 years). Pupils also indicated whether they could recall classroom teaching on 15 food- and health-related issues. Scores were derived representing self-reported frequency of eating foods that were high in fat, and fresh fruits and vegetables. Smoking was found to be associated with lower levels of exercise, consumption of less fresh foods and greater consumption of fatty foods. In addition, consumption of fresh foods was found to be positively correlated with exercise. These findings have implications for the organization of school-based health education efforts and suggest that health education programmes need to adopt an integrated approach rather than treat health behaviours in isolation from each other.