This report profiles undergraduates who were enrolled in U.S. postsecondary institutions in the academic year 1999-2000. It is based on data from the 1999-2000 National Postsecondary Student Aid Study (NPSAS:2000), the fifth in a series of surveys conducted by the U.S. Department of Education. Each NPSAS survey is a comprehensive nationwide study to determine how students and their families pay for postsecondary education. The report begins with an overview that describes the demographic diversity of the undergraduate population. In particular, it documents gender, age, race/ethnicity, parenthood, and the disability status of undergraduates. The overview is followed by a compendium of tables describing in detail all undergraduates with respect to enrollment, student characteristics, financial aid receipt, participation in community service, and remedial coursetaking. The estimates in this report were produced using the National Center for Education Statistics Data Analysis System, a microcomputer application that allows users to specify and generate tables for the NPSAS:2000 undergraduate survey. This profile suggests that the postsecondary education system in the United States offers opportunities to a diversegroup of individuals. In spite of the enrollment opportunities, however, gaining access to postsecondary education does not necessarily lead to obtaining a degree or certificate. (Contains 9 figures, 45 tables, and 17 references.) (SLD)