In France, drug abuse among the young population first appeared at the end of the sixties. Repressive and therapeutic measures were then combined and specific sanitary structures set up. The authors describe the historical and social backgrounds of this phenomenon and review the sources of relevant statistical information records of offences against the drug law; statistics of special care centres; epidemiological studies on confirmed drug addicts. These sources are various and the approaches quite different. However, they reveal socio-demographic characteristics of French drug abusers and a typology of substances abused and identify different periods in drug career. These studies also allow identification and evaluation of risk factors of drug abuse by typological analysis and by psychometric tests. The authors outline the benefit of collaboration between researchers and clinicians: partial interviews of small addicted populations and national surveys provide complementary information. Systematic epidemiological studies would give global measures of changes in addiction.