The advent of antiretroviral therapy (ART) in 1996 brought with it an urgent need to develop models of health care delivery that could enable its effective and equitable delivery, especially to patients living in poverty. Community-based care, which stretches from patient homes and communities—where chronic infectious diseases are often best managed—to modern health centers and hospitals, offers such a model, providing access to proximate HIV care and minimizing structural barriers to retention. We first review the recent literature on community-based ART programs in low- and low-to-middle-income country settings and document two key principles that guide effective programs: decentralization of ART services and long-term retention of patients in care. We then discuss the evolution of the community-based programs of Partners In Health (PIH), a nongovernmental organization committed to providing a preferential option for the poor in health care, in Haiti and several countries in sub-Saharan Africa, Latin America, Russia and Kazakhstan. As one of the first organizations to treat patients with HIV in low-income settings and a pioneer of the community-based approach to ART delivery, PIH has achieved both decentralization and excellent retention through the application of an accompaniment model that engages community health workers in the delivery of medicines, the provision of social support and education, and the linkage between communities and clinics. We conclude by showing how PIH has leveraged its HIV care delivery platforms to simultaneously strengthen health systems and address the broader burden of disease in the places in which it works.