This article describes findings from interviews of parents targeted for outreach efforts that encouraged them to use Medicaid's Early and Periodic Screening, Diagnosis and Treatment(EPSDT) Program. Begun in the 1970s, the EPSDT program held out the promise of ensuring that needy children would receive comprehensive preventive care. With only one-third of eligible children in the United States receiving EPSDT checkups, the program has yet to fulfill its promise. This study sought to understand parents' perceptions of barriers to using EPSDT by interviewing (a) 110 parents who did not schedule EPSDT checkups for their children after being exposed to outreach efforts and (b) 30 parents who did. Although the EPSDT Program is designed to provide health care at no charge and to provide assistance with appointment scheduling and transportation, these low-income parents identified significant barriers to care. Reasons for not using EPSDT services included (a) competing family or personal issues and priorities; (b) perceived or actual barriers in the health care system; and (c) issues related directly to problems with the outreach efforts. Parents who successfully negotiated these barriers and received EPSDT services encountered additional barriers, for example, scheduling and transportation difficulties, long waiting room times, or care that they perceived to be either unresponsive to their medical needs or interpersonally disrespectful. The implications for future outreach efforts and improving access to preventive health care services are discussed.