In the Abecedarian Project, a prospective randomized trial, the effects of early educational intervention on patterns of cognitive and academic development among poor, minority children were examined. Participants in the follow-up were 104 of the original 111 participants in the study (98% African American). Early treatment was full-time, high-quality, educational child care from infancy to age 5. Cognitive test scores collected between the ages of 3 and 21 years and academic test scores from 8 to 21 years were analyzed. Treated children, on average, attained higher scores on both cognitive and academic tests, with moderate to large treatment effect sizes observed through age 21. Preschool cognitive gains accounted for a substantial portion of treatment differences in the development of reading and math skills. Intensive early childhood education can have long-lasting effects on cognitive and academic development.