Young children's experiences outside of both home and school are important for their development. As women have entered the labor force, child care has become an increasingly important context for child development. Child care experiences prior to school entry have been well-documented as important influences on children's academic and socioemotional development. However, less is known about the importance of non-parental, out-of-school care for young school-age children's development. Using a nationally representative sample of kindergartners (n=16,888), this study examined the relationship between child care experiences during the kindergarten year and children's academic and socioemotional skills. Given that the amount of time available for child care is by definition related to the type of kindergarten a child attends, differences in the relationship between child care and child development were explored separately by full- and part-day kindergarten. Results showed that across both types of kindergarten, more hours of center care during the kindergarten year were associated with small improvements in math test scores for all children. Any center child care during the kindergarten year was associated with increased problem behavior and decreased prosocial skills, even after accounting for a large number of confounding factors. Differences by family income and child gender were also investigated. Implications for policy and practice are discussed. (Contains 4 tables.)