The purpose of this longitudinal study was to describe kindergarten children's abilities, evaluate the effect of teacher expectations on kindergarten performance, and explore the predictive validity of kindergarten performance for later reading ability. An original sample of approximately 450 kindergarten children was tested with a school readiness measure. By the time the children were tested on reading ability at the end of third grade, 122 children remained in the sample. For entering kindergarteners, performance on school readiness test tasks was significantly related to socioeconomic status, age (older children performed better), and sex (girls performed better). Attending preschool and watching "Sesame Street" were also found to be slightly related to readiness task ability. Kindergarten children in 1971 performed better on most school-related tasks, except those involving perceptual-motor skills, than did kindergarten children in 1968. Teacher judgments of the subjects' abilities at the end of the kindergarten year were better predictors of the subjects' reading success in first, second, and third grades than school readiness test scores. Past reading ability was found to be the best predictor of future reading ability. Through the primary grades, girls continued to perform better than boys in the measured abilities. Data showed that children who stayed in the same school from kindergarten through third grade read better than the class as a whole, when all other factors were held constant. (BRT)