To assess the effects of mandatory sentences on the judicial processing of domestic abuse cases, this study examined half of all serious and aggravated misdemeanor domestic abuse assault cases filed in one Iowa county in the year immediately preceding and in the 2 years immediately following the 1991 changes in the domestic abuse provisions of the law. In addition to examining the case records from these 3 years, researchers discussed the impact of mandatory penalties with individuals involved in the judicial processing of domestic abuse cases during these years. Findings show that all defendants convicted of a domestic abuse charge subsequent to the use of mandatory penalties served time in jail. Also, after the initial phase-in period, all were sentenced to participate in batterers' education. The evidence also suggests that the expansion of the category of penalty- enhanced charges increased the severity of penalties for repeat offenders. In this respect, the 1991 amendments had the desired impact in this county; however, the study also found that mandatory penalties decreased the conviction rate by reducing the incentive for defendants to plead guilty and increasing the importance of the victim in obtaining convictions. Questions raised by this finding are identified. 3 tables, 1 figure, 7 notes, and 16 references