Imprisonment comprises ordinary fixed term imprisonment, imprisonment for up to 3 months implemented as intensive supervision with electronic monitoring in the community, and imprisonment for up to 3 months combined with probation. Probation comprises ordinary probation, probation with a condition of contract treatment, probation with a condition of community service, and probation combined with a short imprisonment. Computerized information on all persons subject to these sanctions is maintained in the central administration of the SPPS. This information relates to approximately 90,000 present or past offenders. All data used in this study were taken from the SPPS computer files. The results show that, for those released from prison between 1994 and 1999, recidivism increased progressively with length of follow-up period. The difference between the 1 year and 3 year follow-ups was between 15 and 20 percent. Recidivism also increased with each successive year’s cohort of released prisoners. These increases probably reflect the change in the character of the prison population resulting from the legislative changes taking place. These changes were the introduction of intensive supervision and of a conditional sentence with community service. For released prisoners received anew into prison, the increase in imprisoned recidivists varied between 13 and 18 percent with the increasing length of follow-up. For recidivism following ordinary probation, the recidivism rate increased with the longer follow-up periods. For probationers under contract treatment, the differences between the annual populations were small but increased with longer follow-up periods. For probation and a condition of community service, recidivism was between 25 to 30 percent 2 years after the start of the sanction, and 29 to 32 percent after 3 years. Recidivism rates for probation combined with short-term imprisonment were high; 34 to 38 percent had recidivated. For intensive supervision with electronic monitoring, the recidivism rates were virtually constant at 4 percent with a 1 year follow-up, 8-9 percent with a 2 year follow-up, and 12 to 14 percent with a 3 year follow-up. 32 tables