The data on consumption of cannabis in the young people are well documented on the other hand this consumption is less described in subjects presenting a drug dependency. The consumption of cannabis in 2006 and the principal tendencies since 2004 were studied from the OPPIDUM (Observation of Illegal Drugs and Misuse of Psychotropic Medications) program's. OPPIDUM is an annual transverse national study pharmaco-epidemiologic which recruits subjects presenting a drug dependency or benefiting of a maintenance treatment. In October 2006, 3743 subjects were included. Thirty eight per cent (n=1437) of them are consumers of cannabis, among them 27% announced consumed only cannabis and 73% consumed it with other psychoactive substances. The consumers of cannabis alone are younger, have better social-economical indicators and presented consumption of cannabis in term of abuse and dependence more important. This study underlines the problems of the polyconsommation. No change related to the characteristics of consumers of cannabis was observed between 2004 and 2006. This study underline the presence of two groups of consumers of cannabis presented in structures of care who are different on level of the social-economical indicators and its consumptions.