Questionnaire responses will be matched to indicators of disease progression and treatment history drawn from patients' medical records. The initial one-year analysis will compare outcomes for groups of patients stratified by disease stage and treatment duration. Longitudinal analysis will compare outcomes before and after the initiation of ART; each participant's responses and medical outcomes will be compared with his or her own previous results and with those of other participants at a similar stage of disease progression or treatment duration. This study will generate information needed to sustain large-scale treatment interventions, improve the focus and management of treatment delivery programs, and provide a better understanding of barriers to treatment adherence among HIV infected South African patients.