Compared were the academic achievement, personal and social adjustment, and special education referral rates of early, middle, and late school entrants. It was hypothesized that: (1) there is a significant relationship between entry age and achievement and adjustment variables; (2) achievement and adjustment are significantly different among early, middle, and late school entrants; and (3) early, middle, and late entrants differ significantly in special education referral rates. A total of 83 students of 5-12 years of age who attended grades 1-6 of a small, private, parochial school participated. Data on subjects' academic achievement, and personal and social adjustment, were obtained. Significant differences were found among the groups on: (1) Iowa Mathematics Achievement scores; (2) scores on the Brigance K-1 Screening Test; and (3) personal and social adjustment ratings from student report cards. In addition, a significant relationship was found between rate of referral for special education service and entry age status. It is concluded that findings support the establishment of a September 1st cutoff date for entry to first grade. About 100 references are cited. Related materials, including examples of report cards, a school adjustment checklist, and a survey of teachers' beliefs and classroom practices, are appended. (RH)