The purposes of this article are (a) to present the results of a federally funded study conducted by the Research Triangle Institute concerning the application of categor- ical and noncategorical special education in both state and local education agencies and (b) to illustrate how the case study as a rigorous research strategy (Yin, 1989, 1994) was applied to this policy issue in special education. These purposes are complementary, one focusing on the primary quaiitative methods and procedures of the study, the other focusing on the findings and conclusions relative to a current issue in the delivery of special education and related services. Thus, although the format of this article follows that of the traditional research study, we discuss not only the findings relevant to the implementation of categorical and noncategorical special education, but also the advantages and limitations of case study methodology, which increasingly is being used to study policy issues in special education.