This followup study, one of a series of documents assessing the University of Western Ontario Preschool Project, examines the long range effects of the Project on the performance of children from low income families after entering the public schools. This study summarizes data accumulated by the end of the academic year 1977-78 and describes subject performance at three grade levels (Kindergarten, Grade 1 and Grade 2). Two groups of preschool program graduates (one group including children who had started preschool as 3-year-olds, another including children who had started preschool as 4-year-olds) were compared with a group of control children who had begun kindergarten as 5-year-olds without prior preschool or group care experience. Measures were used to assess social adjustment as well as cognitive competence, intellectual ability and academic achievement. The results so far indicate that preschool graduates have maintained their preschool IQ and other gains; their academic achievements have been generally satisfactory and have been superior to those of the controls; all of the preschool graduates have been promoted each year, but several of the controls have repeated a grade. In general, children who started preschool as 3-year-olds appear to have made greater initial cognitive gains than children in the other groups, and have so far maintained these gains. (Author/SE)