Sesame Street is one of the largest early childhood interventions ever to take place. It was introduced in 1969 as an educational, early childhood program with the explicit goal of preparing preschool age children for school entry. Millions of children watched a typical episode in its early years. Well-designed studies at its inception provided evidence that watching the show generated an immediate and sizeable increase in test scores. In this paper we investigate whether the first cohorts of preschool children exposed to Sesame Street experienced improved outcomes subsequently. We implement an instrumental variables strategy exploiting limitations in television technology generated by distance to a broadcast tower and UHF versus VHF transmission to distinguish counties by Sesame Street reception quality. We relate this geographic variation to outcomes in Census data including grade-for-age status in 1980, educational attainment in 1990, and labor market outcomes in 2000. The results indicate that Sesame Street accomplished its goal of improving school readiness; preschool-aged children in areas with better reception when it was introduced were more likely to advance through school as appropriate for their age. This effect is particularly pronounced for boys and non-Hispanic, black children, as well as children living in economically disadvantaged areas. The evidence regarding the impact on ultimate educational attainment and labor market outcomes is inconclusive. (author abstract)