BACKGROUND: Post-allogeneic haematopoietic stem cell transplantation (HSCT) membranous nephropathy (MN), a rare complication of HSCT, remains an ill-defined entity. We describe the clinical and biological characteristics and outcome of five patients with post-HSCT MN, review the previously reported cases and discuss the pathogenic aspects of this nephropathy. METHODS: Cases were identified by using a questionnaire sent to nephrologists and pathologists in French university and general hospitals. Medical records and kidney biopsy specimens were reviewed and relevant data were collected. Moreover, the IgG subclasses in glomerular deposits and the presence of chimeric renal cells were studied. RESULTS: Five patients were identified. All had a history of chronic graft-vs-host disease (cGVHD) and all had active manifestations of cGVHD at MN diagnosis. Mean time between HSCT and diagnosis of MN was 24.4 months. Renal insufficiency was present in four patients. Renal biopsy examination showed typical features of MN in all patients. IgG1 and IgG4 were the predominant IgG subclasses in the glomerular deposits. No chimeric glomerular cell was detected. Initial treatment for MN consisted in corticosteroids and immunosuppressors (ciclosporin, mycophenolate mofetil, rituximab, chlorambucil) in all patients. Complete remission of nephrotic syndrome (NS) occurred in two patients, partial remission in one patient, while treatment was inefficacious in one (data not available for one patient). Most interestingly, the evolution of NS paralleled the evolution of cGVHD in all patients. CONCLUSION: Our data suggest an association between cGVHD and post-HSCT MN. Treatment, mainly steroids and ciclosporin, should be aimed at the control of acute manifestations of cGVHD.