[en] Today the smoker carries a risk of mortality 70% higher compared to the nonsmoker. In Belgium active smoking is indisputably the most important cause of avoidable death. In 2004 it appears that 27% of the belgian population was smoking. This review describes the comorbidity associated with active tobacco consumption and defines the concepts of dependence and smoking cessation. It also identifies the three factors which determine the success of smoking cessation, i.e. the degree of nicotinic dependence, the presence of anxio-depressive disorders and the importance of the motivation to the stop.