58,000 people live with HIV/AIDS in Canada. British Columbia houses 20% of national infections. The BC Centre for Excellence in HIV/AIDS (BCCfE) estimates that there are 2,000 HIV+ people in BC who are eligible for HIV treatment and not accessing it, either because they are unaware of their infection or not appropriately linked to care. It is believed that a large percentage of these individuals may be Aboriginal, given their disproportionate risk of acquiring HIV, and limited access to treatment. As HAART access is expanded to HIV-positive communities throughout BC, additional research is necessary to understand Aboriginal risk factors for acquiring HIV, to explain their limited access to HIV treatment and care, and to understand their elevated mortality while receiving HAART. Overall, my PhD research seeks to answer the question: How do social, sexual and drug-using networks influence Aboriginal risk for HIV acquisition, HIV treatment access and HAART outcomes. I will explore three hypotheses: 1) Socio-demographic and economic status, injection drug use and risky sexual behavior, are primary risk factors for HIV infection among Aboriginals in BC; 2) Socio-cultural beliefs and drug addiction perpetuate limited treatment access among Aboriginals in BC; 3) Lifestyle issues influence poor treatment outcomes among Aboriginals on HAART in BC. I intend to employ social, sexual and drug-use networking techniques that have been pre-validated for HIV/AIDS epidemiological study. An initial pool of consenting HIV-positive Aboriginal adults on HAART (n=30) will be asked to recruit up to 10 people from their sexual and/or drug use network, defined as someone with whom they have had sex and/or done injection drugs with, within the preceding 2 months. A maximum of 300 participants will be recruited through this technique (n=300). Mathematical modelling techniques will be used to analyze the impacts of sexual and drug use networks on Aboriginals' HIV risk behavior, treatmenta access and treatment outcomes. This research will be coordinated from the British Columbia Centre for Excellence in HIV/AIDS, and carried out at the Vancouver Native Health Society.