This is a proposal for continuation of support for a postdoctoral research training program in Neuroepidemiology. To our knowledge, it is the oldest and one of the only NIH-funded Neuroepidemiology training programs in the US. Neuroepidemiology addresses the antecedents and risk factors, natural history, and, ultimately, the prevention of neurological diseases, and there is a critical need for clinician-scientists and public health scientists to study the epidemiology of neurological disorders in light of the aging of the population and advances in available tools to study these issues. The objective of the program is to prepare neurologists and other research scientists for research careers in the epidemiology of neurologic disorders. Since its inception, the program has trained neurologists and neuroscientists who are now professors or career research scientists at major academic institutions, the NIH, and elsewhere. The program, which completed its 37thyear of funding, capitalizes on the strengths of the Department of Neurology (Vagelos College of Physicians and Surgeons), the Departments of Epidemiology and Biostatistics (Mailman School of Public Health [MSPH]), and the inter-disciplinary structure of the Gertrude H. Sergievsky Center, all at Columbia University Medical Center. The program provides stimulating training in a research environment for developing neuroscientists who plan to use epidemiologic methods to study diseases of the nervous system, and have as a career goal a research or academic position. The structured, didactic training provided by the curriculum at the MSPH, combined with the opportunity to participate in ongoing epidemiologic studies of neurologic disease conducted by program faculty, provides trainees with optimal training for academic positions. Trainees will have the opportunity to work on large ongoing epidemiological studies utilizing different study designs, including case-control and prospective cohort studies such as the Northern Manhattan Study, the Washington Heights-Inwood Community Aging Project, the Consortium on Risk for Early Onset Parkinson's Disease, and others. Past trainees have successfully competed for independent funding from the NIH and other sources. We request support for four MD/DO neurologists or appropriate postdoctoral neuroscientists (PhD or equivalent) each year for five years. All trainees spend two years in the program, during which time sequenced didactic course work in epidemiology and biostatistics will be integrated with increasingly independent research activity. A degree (MS in Epidemiology) is the recommended course for most trainees. Trainees also meet weekly to present research and grant plans, and to discuss career development.