Glomerulonephritis with proteinuria of sufficient degree to manifest the nephrotic syndrome followed aplastic crises induced by human parvovirus (B19) in seven patients with homozygous sickle-cell disease, within 7 days in five patients and 6-7 weeks in two. Segmental proliferative glomerulosclerosis was found in the fifth patient who had a biopsy 4 months later. One patient recovered completely, one died in chronic renal failure after 3 months, and the others had impaired creatinine clearance, four with continuing proteinuria.