This study investigated whether a self-concept enhancement program would effect significant change in the self-concepts of 4-year-old middle class preschoolers as compared with classmates not in the program. All participating children (N=52) were pre- and posttested using the Thomas Self-Concept Values Test and the Developmental Profile. The experimental group consisted of 34 children, who participated in 33 sessions (one 20- to 30-minute session per day) over an 11-week period. Activities focused on enhancement of the physical, intellectual, emotional, and social self. The control group consisted of 18 children. Results indicated the experimental group did show more significant changes in self-concept scores than the control group. Parallels were observed between significant self-concept scale changes in the experimental group and certain specific self-concept enhancement activities. Teachers' ratings and children's self-reports indicated very significant increases on the factor scales of happiness, sociability, sharing, less fear of things and people, independence, self-confidence, and sensitivity to others. The control group showed only a significant increase in self-awareness. This study has underscored the need for self-concept enhancement programs as a crucial aspect of preschool experience. (DP)