In the US there is a striking racial disparity in the risk of end-stage renal disease among HIV-infected people: the incidence in blacks that is approximately 50-times higher than that in whites. However, little is known about the epidemiology and implications of kidney disease (KD) among HIV-infected blacks in sub-Saharan Africa, where two-thirds of the global population of people living with HIV reside. As combination antiretroviral therapy (CART) is increasingly available in developing countries, it is important to appraise how non-infectious HIV-associated comorbid conditions affect outcomes. We propose to characterize HIV-related KD by measuring two intrinsic markers of kidney function (creatinine and cystatin C) in stored serum samples from 3,000 participants in a large, community-based cohort in the Rakai District of Uganda. Our aims are 1) to ''''compare the prevalence and incidence of KD in HIV-infected and HIV-seronegative subjects residing in the same community, 2) evaluate the effect of CART on the rate of kidney function decline in HIV-infected subjects with KD, 3) compare the correlation coefficients of creatinine and cystatin C-based estimates of kidney function in HIV-infected and HIV-seronegative subjects, and 4) determine the association between kidney function and mortality in HIV-infected participants. This proposal is well-suited to the priorities of the JHU Global Health Research Pilot Grants because it targets an understudied issue of substantial importance to sub-Saharan Africa, it fosters new collaborations between the JHU Schools of Medicine and Public Health and the Rakai Health Sciences Program, and it is intended to provide preliminary data for extramurally-funded prospective research.