Currently, 34% of people living with HIV eligible for treatment (WHO 2013 Guidelines) have access to antiretroviral therapy. In contrast, it was estimated that by 2009, 4% of all HIV-positive people who inject drugs (range 2–18%) worldwide were receiving antiretroviral therapy. Given the breadth of injecting drug use and the disproportionate HIV-related risks among people who inject drugs, preventing HIV and other harms among people who inject drugs—and providing them with effective treatment, care and support—are essential components of a sound, effective national response. The active engagement of people who inject drugs in the planning, implementation and monitoring of HIV programmes is critical to success.