We use observations from the NICHD Study of Early Child Care and Youth Development (SECCYD) to compare structural and process characteristics of child care centers, family child care homes (nonrelative care in a home setting) and care by relatives for 2, 3-and 4 ½-year-old children. Type of care differences in structural and caregiver characteristics were consistent across ages: centers had higher child-to-adult ratios and bigger groups; centers had caregivers with better education, more training in early childhood, and less traditional beliefs about child rearing. Children in centers experienced more cognitive stimulation, less frequent language interactions with adults, less frequent negative interactions with adults, and less television viewing than did those in other types of care. In centers and family child care homes compared to relative settings, children engaged in more positive and negative interactions with peers and spent more time in transition and unoccupied. Curvilinear associations were found between structural features of care and family income, particularly for caregiver education and training. In contrast, process measures of caregiving rose monotonically with family income. Children from high-income families experienced more sensitive care, more cognitive stimulation, and fewer negative interactions with adults than did those from low-income families. We interpret the findings by linking the structural features and caregiver training to the cognitive and social processes observed in different types of care. Future research designed to understand the influences of child care on children's behavior might benefit from using this more nuanced description of child care experiences.Child care quality is a well-documented predictor of children's intellectual and social development, but recent evidence indicates that type of care may be important independently of "global" ratings of quality. A recurrent finding in the literature is that children who participate in center-based arrangements-including Head Start-during their infant and preschool years perform better on cognitive and language development and show better preacademic skills than children who spend an equivalent amount of time in child care homes or relative care of comparable quality (Garces, Thomas, & Currie, 2002; NICHD Early Child Care Research Network [ECCRN], 2000a; NICHD ECCRN & Duncan, 2003).The relations of type of care to children's social behavior are more uncertain. Two longitudinal studies of large, national samples have shown that children with more center care experience were rated by caregivers and elementary school teachers as having more behavior problems and less self control than those who had not experienced center care (Magnuson, Ruhm, & Waldfogel, 2007; NICHD 2002;2003a). Most longitudinal investigations of children from Contact author Chantelle Dowsett, Human Development & Family Sciences, University of Texas at Austin, 1 University Station/A2700, Austin, TX 78712; 512-471-3141; E-mail: dowsettcj@mail.utexa...