Since the effective date of the new code, January 1, 1978, and up to October 31, 1984, there were 780 offenders committed to the Iowa prison system with mandatory minimum sentences. The distribution of these cases among the 5 classes of mandatory minimum sentences is as follows: delivery of narcotics to juvenile, 4; delivery of controlled substance (except marijuana), 149; use of firearm in forcible entry, 302; habitual offender, 79; and prior forcible felony, 246. These 780 commitments represent 9.5 percent of the total commitments during the 6-year period. Ninety-one of the 780 offenders have expired their mandatory minimums and have left the prison system; these offenders served an average of 42.3 months prior to their release. An analysis of a random sample of 1,000 offenders who left the prison system by parole or expiration of sentence during the period 1976 to 1980 indicates that 383 of the offenders exhibited at least one of the characteristics associated with the current mandatory minimums. These 383 offenders served an average of 33 months prior to release. Further, the 383 offenders studied exhibited only slightly higher recidivism rates than did the other 617 offenders. This result casts doubt on the utility of the mandatory minimums for reducing the threat to society posed by the release of convicted felons on parole. Twelve tables are included.