The study reported here examined the long term performance of three groups of children who attended the Head Start program in the Montgomery County (Maryland) Public Schools. The students attended Head Start as preschoolers in 1970-71, 1974-75, and 1978-79, and were in grades 4, 8, and 12, respectively, during the 1983-84 school year. The following two research questions were addressed: (1) does participating in Head Start have any long term effects, and (2) how does the long term performance of the Head Start graduates compare to that of other students in the school system. The study examined the impact of Head Start participation (question 1) by comparing the performance of students who attended Head Start with that of a group of students who applied to Head Start but were not admitted. Overall performance (question 2) was assessed by comparing the performance of Head Start graduates to that of all other students in the school system born in the same year. Specifically examined were the following: grade retentions, special education placements, standardized test performance, grades, type of courses selected (honors, remedial), and attendance. Findings generally indicated positive effects for all three groups, although weak design prevented the effects from being seen in the fourth and eighth grade groups. (DST)