AL amyloidosis is an infiltrative disorder characterized by the extracellular deposition of insoluble fibrillar immunoglobulin light chains whose production results from a plasma cell dyscrasia. Treatment with melphalan has resulted in an improvement in a few patients. Recently, intensive chemotherapy followed by autologous or syngeneic stem cell support has been shown to offer potential benefit. Allogeneic stem cell support after intensive therapy would retain the benefits of autologous transplantation, with the additional advantages of a tumor-free graft and of a possible graft-versus-tumor effect. We report a patient with AL amyloidosis and significant proteinuria. She improved after an allogeneic bone marrow transplantation.