Black men who have sex with men (MSM), especially young MSM, are more likely to contract Human Immunodeficiency Virus (HIV) than MSM of other races. However, Black MSM consistently report comparable or fewer individual risk behaviors than MSM of other races. Research thus far has largely targeted individual risk factors and has been unable to account for the mechanisms driving this racial disparity. In addition, although individual risk behaviors occur within particular risk environments, little research examining HIV racial disparities has acknowledged that substance use and other HIV risk behaviors are socially and spatially dependent. Emerging research with Black MSM documents racial/ethnic differences in the individual, venue, and neighborhood level networks of young men who have sex with men (YMSM). These findings suggest that although rates of drug use and other individual risk behaviors may be lower among Black YMSM than other racial/ethnic groups, their consequences may be different due to the nature of the risk environments experienced by these young men. The overall objective of this project was to contribute to knowledge about structural mechanisms (e.g., stigma, discrimination, and resource inequality) that shape risk environments, which in turn shape consequences of substance use and other HIV risk behaviors for YMSM of different races/ethnicities. However, quantitative data describing these social and spatial contexts (i.e., the structure of individual, venue, and neighborhood networks) has limited capacity to explore and explain these complex phenomena, and interpreting these data is problematic without the incorporation of the voices, lived experiences, and insights of YMSM themselves. Therefore, thisstudy used an innovative mixed methods approach to visualize and guide the interpretation of individual, venue, and neighborhood level networks captured within an existing NIH-funded cohort of YMSM. Using an explanatory sequential design, multilevel network and geospatial data were visualized (Phase 1) and subsequently used to guide interviews with YMSM (Phase 2). Grounded theory was used to analyze interview data, leading to a theory of mechanisms that shape HIV racial disparities in this population. The overall project had two aims: 1) demonstrate several mechanisms through networks at the individual, venue, and neighborhood levels form risk environments that shape substance use and HIV risk for White, Black, and Hispanic/Latino YMSM, and 2) demonstrate several structural mechanisms, such as stigma, discrimination, and resource inequality, that shape the individual, venue, and neighborhood level networks and risk environments of White, Black, and Hispanic/Latino YMSM.