HIV was first discovered in the United States nearly 30 years ago. Since that time MSM have been more severely impacted by HIV/AIDS than any other social group in the nation. The health disparities suffered by MSM are profound: while MSM account for less than 5% of all men in most behavioral surveys, this sub- population currently accounts for nearly 60% of all new HIV infections in the United States. A recent CDC analysis calculated that MSM are 60 and 61 times more likely to be infected with HIV and syphilis, respectively, than heterosexual men and 54 and 93 times more likely to be infected with HIV and syphilis, respectively, than women. A clear focus on the HIV prevention among MSM is therefore essential if we are to successfully prevent ongoing HIV transmission in the United States. Findings from HIV/AIDS research typically support the conclusion that gay men suffer far higher rates of numerous psychosocial health problems than those found among heterosexual men. Evidence is also accruing to show that these psychosocial health problems cluster among gay men, amplify the effects of each other and work to fuel risk for HIV/AIDS. These intertwining epidemics or syndemics are the focus of a growing literature and suggest that if we are to find more effective ways to respond to the AIDS epidemic among MSM, we must find ways to address multiple psychosocial health conditions that fuel HIV risk and in themselves constitute important health risks in this population. This T32 application requests initial support for two pre-doctoral and one post-doctoral trainee to for training in research on HIV-related health disparities among MSM at the University of Pittsburgh, with increased support to four pre-doctoral and two post-doctoral positions by the end of the five year grant period. The T32 training program will drawn on the resources of an existent Certificate Program in LGBT Health, itself given within the context of several internationally-recognized doctoral and post-doctoral training programs at the Graduate School of Public Health at the University of Pittsburgh (in the Departments of Behavioral and Community Health Sciences, Epidemiology and Infectious Disease and Microbiology). The T32 training program organizes an internationally-recognized group of scholars to participate in trainee. Thus, this program will give trainees a background in health disparities research among MSM, focusing on HIV/AIDS prevention research, all within the context of larger doctoral and post-doctoral training programs situated within a top-ranked graduate school of public health.