The purpose of this study was to determine dental utilization and type of dental services for Medicaid-enrolled adults who had been identified as having intellectual and developmental disabilities (IDD). Using Iowa claims data, the authors identified adults who met any of five IDD criteria for inclusion during calendar year 2005. Service utilization rates, including use of preventive dental, routine restorative, and complex restorative services, were determined. Approximately 60% of adults with IDD had at least one dental visit in 2005. Among adults with at least one dental visit, 83% received a preventive service, 31% a routine restorative service, and 16% a complex dental service. Those age 65 and older had fewer preventive dental services than other age groups. In Iowa, dental utilization for adults 22-64 years of age with IDD was reasonably high (64%) in 2005, but individuals over age 65 had lower utilization (45%).