Medicaid-enrolled children with autism spectrum disorder (ASD) encounter significant barriers to dental care. Iowa's I-Smile Program was implemented in 2006 to improve dental use for all children in Medicaid. This study compared dental home and preventive dental utilization rates for Medicaid-enrolled children by ASD status and within three time periods (pre-implementation, initial implementation, maturation) and determined I-Smile's longitudinal influence on ASD-related dental use disparities. Data from 2002-2011 were analyzed for newly Medicaid-enrolled children aged 3-17 years (N=30,059); identified each child's ASD status; and assessed whether the child had a dental home or utilized preventive dental care. Log-linear regression models were used to generate rate ratios. Analyses were conducted in 2015. In 2003-2011, 9.8% of children with ASD had dental homes compared with 8% of children without ASD; 36.3% of children with ASD utilized preventive care compared to 45.7% of children without ASD. There were no significant differences in dental home rates by ASD status during pre-implementation, initial implementation, or maturation. There were no significant differences in preventive dental utilization by ASD status during pre-implementation or initial implementation, but children with ASD were significantly less likely to utilize preventive care during maturation (rate ratio=0.79, p<0.001). Longitudinal trends in dental home and preventive dental utilization rates were not significant (p=0.54 and p=0.71, respectively). Among newly Medicaid-enrolled children in Iowa's I-Smile Program, those with ASDs were not less likely than those without ASD to have dental homes but were significantly less likely to utilize preventive dental care.