For prison terms of two years or more, the number of prisoners who were 25 years or younger at the time of admission decreased significantly during the study period (29 percent as compared to 48 percent of the admissions); during the same period, the number of inmates above the age of 34 increased dramatically. This phenomenon cannot be interpreted as simply a reflection of changes in Quebec's population or in delinquent behavior. Rather, the aging process results from changed sentencing practices of the courts and changes in penal policy. Thus, the courts increasingly chose to select alternatives to prisonization for younger offenders, thereby causing the dramatic decrease in that prison population. At the same time, society has judged the offenses committed by older inmates (predominantly homicides, sexual offenses, and drug offenses) as more serious than before. The resulting changes in criminal policy and sentencing practices have caused this part of the prison population to rise. 32 references