Two studies were conducted to assess the effectiveness of the Marvelous Me--Preschool Edition (MM-PE) Curriculum Guide, a 12-Session program designed to enhance the self-concepts of preschool children. Study 1 involved 127 middle and upper-middle class midwestern white students, mostly Jewish, from 10 classrooms in 1 nursery school and 1 day-care center. Study 2 involved 58 inner-city black preschool children in Chicago defined as academic at-risk. In both studies, the Purdue Self-Concept Scale for Preschool Children was used as pre- and as post-test. Parents and teachers completed the All About Me Evaluation Checklist after program implementation in both studies, and teachers of the experimental groups in study 1 completed a teacher questionnaire. In study 1, a comparison of experimental (N=72) and control (N=55) students on the pre- and post-test, and the gain from pre- to post-test scores, indicated no significant difference between the two groups. In Study 2, experimental students (N=30) had a significantly higher gain in MM-PE scores than did control students (N=28), although control students also gained from pre- to post-test, probably due to familiarity with the test and maturity. The main conclusion drawn was that at-risk preschool children possibly could benefit the most from a systematic intervention designed to enhance their self-concept. (Thirty-five references and six data tables are included.) (NB)