South Africa has one of the worst and fastest growing HIV epidemics in the world. Highly active antiretroviral therapy (HAART) has been shown both at the individual and public health levels to reduce morbidity, mortality, and vertical and possibly horizontal HIV transmission. However, expenses, feasibility, long-term adherence, and effective delivery of HAART remain formidable barriers, particularly in developing nations. Recently, international initiatives have provided hope for widespread use of HAART at affordable cost in sub-Saharan Africa. Simplified, once-daily HAART regimens with directly observed therapy (DOT) may help to achieve high levels of treatment adherence, a key component for long-term viral suppression and treatment success. Peer advocates have been used to improve adherence with medical therapies in a variety of settings. This study will evaluate the effectiveness and feasibility of DOT using patient-nominated peer supervisors to improve adherence to HAART in HIV infected adults in South Africa.