This report considers the implications for medical education of a global survey of the knowledge, behaviour and attitudes of medical students regarding tobacco. This was conducted in 42 countries derived from all continents. A total of 9326 students (44% women) from 51 medical schools replied anonymously to a multiple choice questionnaire administered in the local language. Student smoking rates varied greatly between countries/regions: daily smoking in men from 2% (Australia) to 48% (one centre in the former USSR); in women from nil in some Asian medical schools to 22% in one European. Though there was some variation between countries and medical schools, there was widespread ignorance of the causal role of smoking in specific diseases; notably coronary artery disease, peripheral vascular disease, emphysema, bladder cancer and neonatal mortality. There were widespread defects in knowledge and motivation regarding counselling patients to quit smoking, with a common failure to appreciate a doctor's responsibilities in prevention. Very few students knew the value of tobacco taxation in reducing consumption. Following our survey we were asked to advise the World Health Organization on a summary of the desirable tobacco content of medical curricula, which has now been issued. The International Union against Tuberculosis and Lung Disease, in cooperation with the European Region of WHO, has circulated the Deans of all European medical schools with a summary of the deficiencies revealed by the European component of the survey, together with a questionnaire on proposed action. A similar initiative is being considered in cooperation with the Western Pacific Region of WHO.