Seven prevention techniques were identified: crisis intervention, 'big brother' programs, job training, residential facilities, information and referral, 'drop-ins,' and street work. These techniques were further grouped into two types of preventive action: the 'prise en charge' which focuses on the client's personal problems; and assistance, which deals with situational contingencies. A classification system permitted grouping of the 34 programs into two overall types. The first could be classified as individualized programs which exclude the general public and specifically address delinquents and potential offenders of either sex above or below 18 years of age. Problems associated with delinquency are almost always on the order of the family or tied to unemployment and poverty. These programs receive their clients primarily from institutional services; some clients volunteer, but none are actively recruited. These programs concentrate on personal problems and include the crisis intervention, 'big brother' programs, job training, and residential facilities. These programs operate in any part of Montreal and in the country as well. The second type of program is classified as a community program, with a focus on the general population, although almost all clients are under 18. Problems associated with delinquency are thought to be a general lack of socioeconomic opportunity or, less frequently, the stigmatizing effects of having entered into the criminal justice system. Most clients come voluntarily, sometimes they are referred by institutions, and some of the programs recruit actively. Mostly known as information and referral, 'drop-in', or street work, these programs use the assistance technique, with the situation and not the individual as the focus of attention. These programs can be found in all parts of Montreal and in the country. Further study of these programs should conentrate on collecting more evaluative data so that these programs can be compared and analyzed for their effectiveness. --in French. (Author abstract modified)