Loss of an allograft caused by anti-GBM antibody-mediated nephritis is a rare complication of renal transplantation in Alport's syndrome. We describe a patient in whom this occurred. He belongs to the subgroup of patients with hereditary nephritis and deafness with an abnormal Goodpasture antigen, and he developed a high level of circulating anti-GBM antibodies within 20 days of transplantation of a kidney with a presumably normal Goodpasture antigen. The antibody titer fell, only to rise again when he developed evidence of acute infection with CMV. Coincident with this second rise in antibody titer he developed an anti-GBM antibody-mediated crescentic nephritis with resultant loss of graft function and transplant nephrectomy. This case provides support for the hypothesis that the abnormality in the basement membrane in some patients with Alport's syndrome involves the Goodpasture antigen, and raises the possibility that viral infection may have triggered autoantibody production.