Research suggests that how children spend their out-of-school hours can significantly affect their social development and school success. The Out-of-School Time Study, conducted by the School-Age Child Care Project at the Wellesley College Center for Research on Women, investigated how young low-income children in three urban communities spent their daytime hours outside of school. The study focused on children aged 4-7, from diverse backgrounds, in Head Start and Transition programs. Using both quantitative and qualitative methods, the study found that two-thirds of the 180 children in the sample spent their out-of-school time with their mothers--a finding that is related to the low labor force participation rate of their mothers. Of the children who did spend some time in the care of others, older siblings were the most common nonmaternal caregivers, followed by fathers. A relatively high percentage of young children regularly spent time without adult supervision, and watching television was by far the most frequent out-of-school activity. However, notable variations among the three cities suggested that the availability and accessibility of neighborhood resources played a decisive role in how children spent out-of-school time. In neighborhoods where crime was a major concern, parents perceived watching television as the best available choice for keeping children safe and occupied. The study found a discontinuity between children's actual after-school activities and what their parents wanted for them. Approximately one-third of the mothers studied worked outside the home, and more were married than single. The determinant of employment was not marriage per se but the availability of child care from another adult in the household. Employed mothers relied on multiple child care arrangements and experienced child care problems if relatives were not willing to care for the children. The publication concludes with recommendations for service providers, policy makers, advocates, and researchers. (Contains 127 references.) (WJC)