This study assessed the effects of Instrumental Enrichment (IE) instruction with minority students on a non-verbal measure of students' intelligence (the Progressive Matrices test), on students' report card marks, and on students' City-Wide Test nationally-normed reading and mathematics scores in the School District of Philadelphia (Pennsylvania). Seven teachers who had been trained in IE techniques and taught fifth grade through seventh grade selected one of their classes to participate in the study. Two of the selected classes served special education students. The study shows that: (1) students in classes that had more IE sessions scored higher on the Progressive Matrices test than did students in classes that had fewer sessions; (2) for special education students, Progressive Matrices scores improved, but at a slower rate than did regular education students' scores; (3) up to about 30 IE sessions improve regular education students' English, reading, science, and social studies report card marks, but a larger number of sessions may have interfered with attainment; and (4) national-norm based City-Wide Test scores in reading/English/language arts and mathematics were lower for regular-education students in classes that had more IE sessions than others. An appendix contains experimental design details and data analyses. (JB)