A French version of the Addiction Severity Index was used to rate the severity of the problems of 1,054 subjects, who represented the whole of the male clientele admitted for treatment at a center between May 1, 1991, and April 30, 1992. The subjects were divided into two groups: offenders (those who had been convicted of a criminal offense at least once) and non-offenders (all other subjects, whether they had been charged or not). These two subgroups were compared on sociodemographic characteristics, composite scores, and the severity of their situation. Certain statistical tests were performed (Chi Square and Student's t-test) to determine whether differences observed between the two groups were significant. The needs of those drug addicts who had been convicted of a criminal offense were varied. They were particularly urgent in the areas of job-market reintegration, the need to reduce dependence on illegal drugs, and involvement in the delinquent subcultures associated with drug use. Other needs were related to the rebuilding of their family and social environments, which more often than not had been destroyed by a long career of addiction and criminality. These findings suggest that treatment for drug-addicted offenders should focus on persistence in treatment, improvement in social integration by taking charge of the main aspects of one's life, personal support in controlling aggression, basic social skill development, and job market integration. 4 tables and 10 references