Human immunodeficiency virus (HIV) infection can cause a broad spectrum of clinical manifestations, ranging from an asymptomatic carrier state to severe immunodeficiency. The most common renal lesion, HIV-associated nephropathy (HIVAN), is a sclerosing glomerulopathy. However, potentially reversible causes of renal disease in HIV-infected patients should also be considered. We describe two cases of patients with acquired immune-deficiency syndrome (AIDS) who presented with rapidly progressive renal failure but were found to have reversible etiologies. The first case was found to have syphilis and the second, disseminated histoplasmosis; their renal injury resolved after initiation of a third-generation cephalosporin antibiotic and amphotericin B, respectively.