An association between Fanconi's syndrome and renal transplantation has been reported. We report a patient who developed Fanconi's syndrome coinciding with a rejection 4.5 years following living related donor transplantation. Recurrent disease and hyperparathyroidism were ruled out as etiologies of Fanconi's syndrome. The presence of Fanconi's syndrome - associated with rejection in the transplanted kidney - may signify immunologically mediated alterations in tubular function. Antitubular basement membrane antibodies have been reported in renal allograft recipients. Further study into the pathogenesis of Fanconi's syndrome in renal transplantation may shed light on the spectrum of immunologically mediated dysfunction following renal homotransplant.