This study was conducted in order to identify some of the broad characteristics of achievement in science and mathematics by black students. A nationwide sample of nine, thirteen, and seventeen year old students was tested with a series of exercises that were developed to assess science and mathematics performance. The exercises were designed to probe both content and processes across several taxonomic levels. Findings indicated that, compared to the national average, black students as a group experienced problems in mathematics at all age levels, but these were accentuated by age seventeen. In science, a smaller overall gap in performance was found at age nine. This gap narrowed by age thirteen, but widened noticeably at age seventeen. The many tables of data included in this report indicate particular content areas and specific taxonomic levels at which black students experience difficulty. (MK)