Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults. MN can recur after kidney transplantation causing proteinuria, allograft dysfunction and graft failure. In this study we assessed the incidence of MN recurrence utilizing surveillance graft biopsies. The study included 1310 renal allograft recipients from 2000 to 2006. Glomerular diseases were the cause of kidney failure in 28% of patients and 23 (2%) had idiopathic MN. Recurrent MN was diagnosed in eight of 19 patients included in this analysis (42%) 13 +/- 20 months (median = 4; range 2-61 months) after transplant. The initial clinical manifestations of recurrent MN were mild or absent. Urine protein excretion was 825 +/- 959 (64-2286) mg/day and three patients had no proteinuria. Five of seven patients who did not receive additional immunosuppression for MN had significant increases in proteinuria during follow up and three became nephrotic. At diagnosis, light microscopic changes were subtle or absent. All patients had granular glomerular basement membrane deposits of IgG but little or absent C3 by immunofluorescence. Subepithelial deposits were observed in all cases by electron microscopy. In conclusion, idiopathic MN recurred in 42% of patients after transplantation. The initial clinical and histologic manifestations are subtle but the disease is progressive.