Substance-using women who exchange sex for money, drugs or shelter as a means of basic subsistence (ie. survival sex) have remained largely at the periphery of HIV and harm reduction policies and services across Canadian cities. This is notwithstanding global evidence of the multiple harms faced by this population, including high rates of violence and poverty, and enhanced vulnerabilities to HIV transmission among women who smoke or inject drugs. In response, a participatory-action research project was developed in partnership with a local sex work agency to examine the HIV-related vulnerabilities, barriers to accessing care, and impact of current prevention and harm reduction strategies among women in survival sex work. This paper provides a brief background of the health and drug-related harms among substance-using women in survival sex work, and outlines the development and methodology of a community-based HIV prevention research project partnership. In doing so, we discuss some of the strengths and challenges of community-based HIV prevention research, as well as some key ethical considerations, in the context of street-level sex work in an urban setting.