Recent findings in idiopathic membranous nephropathy (MN) suggest that in most patients, the disease is because of anti-phospholipase A(2) receptor (PLA(2) R1) autoantibodies. Our aim was to analyze the prevalence and significance of anti-PLA(2) R1 antibodies in recurrent and de novo MN after transplantation. We assessed circulating PLA(2) R1 autoantibodies by a direct immunofluorescence assay based on human embryonic kidney cells transfected with a PLA(2) R1 cDNA, and the presence of PLA(2) R1 antigen in immune deposits. We showed that PLA(2) R1 was involved in 5 of 10 patients with recurrent MN, but in none of the 9 patients with de novo MN. We also showed a marked heterogeneity in the kinetics and titers of anti-PLA(2) R1, which may relate to different pathogenic potential. We provide evidence that some patients with PLA(2) R1-related idiopathic MN and anti-PLA(2) R1 antibodies at the time of transplantation will not develop recurrence. Because PLA(2) R1 autoantibody was not always associated with recurrence, its predictive value should be carefully analyzed in prospective studies.