As part of a study to investigate the immediate and long term effects of preschool upon educationally advantaged children, data from three waves of preschool-age subjects (N=291) and followup data on two waves of kindergarten-age subjects (N=171) were analyzed. All children in the sample were determined to be educationally advantaged, and all demonstrated remarkable intellectual capabilities. Five measures were selected for preschool testing. These included (1) the Test of Motor Abilities for Young Children, (2) the Slosson Intelligence Test, (3) the Gesell School Readiness Test (GSRT), (4) the Early Childhood Self-Concept Index, and (5) the California Preschool Social Competency Scale (CPSCS). For kindergarten testing, two measures were employed: the CPSCS and the GSRT. Findings indicated variation of mean I.Q. scores across all three waves favoring subjects who had attended preschool. In the first two waves of preschool subjects, variation between experimental and control groups on the social competency measure was also found to favor those who attended preschool. In kindergarten, social competency gains were shown by children who had attended preschool as well as by those who had not. However, significantly greater gains were made by females who had not attended preschool. Further study is being conducted to determine whether these differences can indeed be attributed to preschool attendance. (Author/RH)