We studied renal lesions at biopsy (20 cases) and at autopsy (21 cases) among patients with the acquired immune deficiency syndrome (AIDS). Nephrotic syndrome with concomitant renal insufficiency was most common indication for biopsy. 85 percent of biopsies showed features of HIV associated nephropathy (HIVAN) which include: Focal segmental glomerulosclerosis (FSGS), glomerular collapse and mesangial hyperplasia. These glomerular changes were always accompanied by tubular microcysts and ultrastructurally, tubuloreticular inclusions (TRI) within the glomerular endothelium were often noted. Changes of HIVAN were also seen in two cases who were HIV negative at the time of biopsy but were positive on repeat testing. Minimal change disease, mesangiocapillary glomerulonephritis and diffuse proliferative lupus nephritis were other biopsy lesions. Autopsy findings were HIVAN (33 percent), tubular necrosis and opportunistic infections. We conclude that HIVAN is a distinct clinicopathologic entity that may sometimes be the first manifestation of the underlying disease state.