Smoking is a public health problem that does not spare the medical profession. We set out to determine the prevalence of smoking in medical students in Dakar and to assess their attitudes and knowledge in the face of this problem. A cross sectional study was conducted by means of an auto-questionnaire among 1547 medical students between 3 and 31 May 2001. There were 1061 males (68.6%) and 486 females (31.4%). The overall prevalence of regular or occasional smoking was 34.6%, with 42.8% in the first cycle, 38% in the second and 19% in the third. It was significantly higher among males at 76.4%. The average age of starting smoking ranged from 10 to 22 years and average duration from 5 to 26 years. The influence of fashion was the most frequent initiating factor at 37.4% and 96.6% smoked commercial cigarettes. Nicotine dependence, assessed by the Fagerstrom score, was average in 59.3%, strong in 14% and very strong in 4.7%. 58.8% smoked in public places and 78.2% thought they could give up smoking within the next 5 years. 8.4% were unaware of the effects of tobacco on health and 20.5% of the relationship between tobacco and the diseases quoted. 37.7% of future doctors would not systematically avoid smoking in the presence of patients but 79% wished to ban advertising and 70.4% to ban the use of tobacco in hospitals. 94.4% of students wanted health care workers to be educated about the effects of smoking. Tobacco smoking among medical students has increased between 1989 (28.7%) and 2001 (35.6%). This observation should stimulate the establishment of a course on the pathology of tobacco smoking and the integration of education and prevention within the medical curriculum, increase the awareness of smokers and above all help them stop.