This paper summarizes recent experience of large-scale, nationally representative longitudinal youth transition studies in the United States. Two study series are considered. First is the longitudinal youth cohorts of the U.S. Department of Labors Bureau of Labor Statistics, the National Longitudinal Youth Study, with cohorts that started in 1979 and 1997. The second series is made up of the student cohorts from the National Center for Education Statistics (NCES). The NCES series is comprised of: (1) the National Longitudinal Study of the High School Class of 1972; (2) the High School and Beyond Study; (3) the National Education Longitudinal Study of 1988; and (4) the Education Longitudinal Study of 2002. The first section of this paper supplies an overview of the two sets of studies. The second section compares the studies, pointing out commonalities and differences in approaches to design and method. The third section summarizes the content of the research instruments used in the studies. The fourth and final section discusses some of the research applications of these databases. The first appendix points to further sources of information about the design, content, and findings of the studies, and the second appendix contains more detailed information about the instruments described in the third section. (Contains 5 figures and 14 references.) (SLD)