A 21-year-old male developed massive proteinuria and microscopic hematuria, 1 year after allogeneic BMT for acute lymphoblastic leukemia. These symptoms occurred during an exacerbation of chronic cutaneous graft-versus-host disease (GVHD). Renal biopsy revealed granular deposits of IgG and IgM along the glomerular basement membrane, and subepithelial electron dense deposits. A diagnosis of membranous nephropathy was made. With prednisolone therapy proteinuria decreased gradually, and amelioration of cutaneous lesions was also noted. It was speculated that the disordered immune regulation of chronic GVHD resulted in the development of immune complex nephritis.