Only 67 percent of pediatricians report that they accept all patients with Medicaid who contact them. This study set out to determine whether differences exist in the timeliness of follow-up appointments given to parents of newborns with private insurance compared to parents of newborns with Medicaid coverage. A simulated parent telephone call took place among randomly selected pediatric clinics and practices across eight metropolitan areas. The caller asked for the earliest available appointment for a one-day infant needing routine follow-up after discharge that day. Clinics initially received the call from a parent with either Medicaid or private insurance, and three weeks later received the same call with the patient's insurance status reversed. A timely appointment was considered one that was two calendar days from the day of the call. The study found that out of 401 participating clinics, 20 percent did not accept Medicaid. Availability of a timely follow-up appointment was similar for parents of newborns with Medicaid compared with parents of newborns with private insurance, and between clinics that did and did not accept Medicaid. However, clinics in high poverty areas, where Medicaid is more concentrated, were less likely to provide timely appointments.