The scope and scale of the HIV outbreak that occurred among injection drug users in Vancouver in the late 1990s was unprecedented and resulted in some 2,000 new HIV infections, with incidence rates reaching 18 per 100 person-years. This outbreak, localized mainly in one neighbourhood, cost the Canadian health care system more than 1 billion dollars to diagnose, care and treat. A number of factors combined to stabilize HIV incidence: 1) HIV prevalence became saturated among those at highest risk; 2) several public health policies focused on drug users were implemented, including increased and additional decentralized needle exchange programs, expanded methadone maintenance services, better addiction treatment services, improved housing, and mental health programs; and 3) increased access and expansion of Highly Active Antiretroviral Therapy. To ensure that a similar outbreak never occurs again in Vancouver and other cities, future health policy must consider the political, psychosocial and socioeconomic factors that contributed to this outbreak. These policies must address the unintended adverse consequences of past policies and their repercussions for marginalized individuals living in this community and beyond.