The Center for Interdisciplinary Research on AIDS (CIRA) at Yale University conducts interdisciplinary research directed toward the prevention of HIV infection and the reduction of the negative consequences of the disease in vulnerable and underserved populations. This application requests support to establish an Institutional National Research Service Award Post-Doctoral Fellowship Training Program in HIV prevention research at CIRA. Primary faculty have been selected from the Departments of Epidemiology and Public Health, Psychology, Medicine, and Psychiatry. Three committees will support the Training Program: Administration, Recruitment/Selection, and External Advisory. The CIRA Training Program will offer opportunities to a total of 3 Post- Doctoral Fellows per year for 5 years. The Program will especially seek to increase the number of women and minority scientists in the field. Training Program activities include: (1) research preceptorship and collaboration in on-going HIV research; (2) Training in research methods and ethics; (3) optional coursework; (4) CIRA and HIV-related seminars and colloquia; and (5) Special events (e.g CIRA Science Day). The Fellows' training experience will provide the knowledge and skills necessary to develop a program of research that can be supported by extramural funding. CIRA's proposed Training Program is unique in its integrated, interdisciplinary approach and its focus on traditionally vulnerable and underserved populations.