Persistent unmet preventive and developmental health care needs of children in low-income families are a national concern. Recently, there have been efforts to promote developmental services as part of primary care for all young children. However, there is limited research to determine whether the neediest families are well in universal interventions. In our study, we assessed if disparities persist in utilization of developmental services, well child care, and satisfaction with care among low-, middle-, and high-income families participating in Healthy Steps for Young Children. Healthy Steps is a national experiment that incorporated developmental services into primary care for children from birth to 3 years of age. In the United States, 15 pediatric practices participated in this prospective study. At birth, 2,963 children were enrolled between September 1996 and November 1998 and followed through 33 months of age. The utilization of developmental services, satisfaction with care, and receipt of age-appropriate well child visits were measured at 30-33 months and adjusted for demographic and economic covariates. We found that the adjusted odds of low-income families did not differ from high-income families in receipt of four or more Healthy Steps services, a home visit, or discussing five or more child rearing topics. Low- and middle-income families had reduced adjusted odds of receiving a developmental assessment and books to read. The adjusted odds of low- and middle-income families did not differ from high-income families in being very satisfied with care provided or receiving age-appropriate well child visits. A universal practice-based intervention such as Healthy Steps has the potential to reduce income disparities in the utilization of preventive services, timely well child care, and satisfaction with care.