To determine whether preschool education benefits middle-class elementary school children, a study was conducted which compared the social, motor, and academic progress of kindergarten and elementary school children who had attended a Montessori preschool, another kind of preschool, or no preschool. The sample was chosen according to age, attendance at preschool, and social class. A total of 201 middle-class children between the ages of 64 and 128 months participated in the study. Of those children participating 151 had attended a nursery, day care, or private school prior to entry into kindergarten for 3 or more days a week, for either half or full days. Each of the three groups of subjects contained five age levels roughly corresponding to kindergarten through fourth grade levels. The Developmental Profile II, given in the form of a parent interview, and parent and teacher questionnaires were used to obtain background information and data on children's abilities. The profile indicated the child's development in months on physical, self-help, social, academic, and communication scales. Generally, results indicated that middle-class children in the primary grades, regardless of preschool background, seem to function at the same level. Results and implications are discussed, conclusions are offered, and graphs and tables of data are included in the report. (RH)