Collapsing glomerulopathy is a pattern of renal injury that has emerged along with the epidemic of HIV infection. The disease process is now increasingly recognized in non-HIV patients. In HIV and non-HIV patients the disease shares many clinical and pathologic features, and, we presume, pathogenetic factors. The disease entity is characterized by very heavy proteinuria frequently combined with rapidly progressive renal failure, poor outcome, glomerular collapse with hyperplasia and other degenerative changes of the visceral epithelial cells, and prominent tubulointerstitial injury with frequent microcystic changes. HIV-associated nephropathy has a higher prevalence in blacks, high frequency of intra-endothelial tubuloreticular inclusions, and prominent microcystic tubular changes. These differences, however, are not sufficient to predict the patient's HIV status from the biopsy findings alone. Collapsing glomerulopathy can also develop in association with lymphoproliferative disorders, systemic lupus erythematosus-like and other autoimmune diseases, other immune deficiency syndromes and viral infections, and in the context of immunosuppressive therapy.