Historic changes in the criteria for pathologic diagnosis and classification of lupus membranous nephropathy (LMN) have precluded definitive descriptions of the natural history, prognosis, and treatment of this disorder. The interim practice, based on the 1982 World Health Organization classification system, of admixing membranous and proliferative lupus nephropathies under the rubric of LMN has confounded the medical literature. Cases with mixed histology should be treated according to recommendations for proliferative lupus nephritis. Patients with LMN should be treated early with angiotensin antagonists to minimize proteinuria, as well as lifestyle changes and appropriate drugs to reduce attendant cardiovascular risk factors. In patients with protracted nephrotic syndrome, consideration should be given to immunosuppressive therapies including corticosteroids, cyclosporine, mycophenolate, and cyclophosphamide. Prospective controlled trials clearly are needed to establish solid clinical practice guidelines for use of these drugs and other experimental therapies currently under study in LMN. This is a US government work. There are no restrictions on its use.