Research Findings: The current study examined the impact of daily classroom computer use on the cognitive development of preschool children in 14 urban Head Start classrooms. The sample consisted of 208 predominantly African American low-income children with a mean age of 48.8 months. A quasi-experimental design was used in which 7 classrooms had computers and 7 classrooms served as the control. Assessments were made at baseline and at 6, 12, and 18 months. Hierarchical linear modeling was used to assess differences between the computer and control groups on cognitive developmental trajectories. Children in the computer condition displayed significantly greater increases in quantitative development than did children from the control condition. Practice or Policy: Children's access to computers at home and at school has become increasingly prevalent. However, there is still a substantial disparity in access to technology between different socioeconomic groups. The preschool years may offer a promising opportunity to close this gap in access; however, little is known about the impact of computers on the developing minds of children, particularly those from low-income African American families. Findings from the current study suggest that daily use of computer centers in the Head Start classroom may benefit quantitative outcomes for young children.