Illicit drug use is a major public health concern in British Columbia, most notably the high rates of HIV and Hepatitis C transmission among injection drug users. Additionally, in Vancouver and elsewhere in British Columbia, there is concern regarding escalating rates of crystal methamphetamine (CM) use. The prevalence of CM use is rising internationally, and has been associated with unsafe sexual and injecting practices among specific subpopulations at risk for HIV. However, the potential associations between CM use and sexual and injection-related risk behaviour among marginalized populations in Vancouver have not been thoroughly investigated. Brandon Marshall was previously funded by MSFHR for his Master’s work studying the interactions between drug use and sexual risk behaviour among street youth in Vancouver. He is now continuing his examination of a number of social, environmental, and structural factors that predict frequent CM use and subsequent health-related harms among young injection drug users. He hypothesizes that social disadvantage, impoverished living conditions, frequent exposure to law enforcement, and poor access to health and harm reduction services will be associated with higher frequency and intensity of CM use. This research will help inform evidence-based public health policy and interventions for marginalized populations. Marshall’s findings may be used to develop strategies that seek to reduce the harms associated with CM use, prevent further transmission of HIV and Hepatitis C, and provide better support for youth and injection drug users who are already infected.