This report concerns a patient with IgM AL amyloidosis due to a B cell lymphoproliferative disorder who was successfully treated with VAD and subsequent high-dose melphalan followed by autologous stem cell support. After this chemotherapeutic regimen, the patient showed complete hematological remission and improvement in nephrotic syndrome. These findings suggest that high-dose melphalan may also be effective for lymphoplasmacytoid cells producing monoclonal IgM which are phenotypically distinct from plasma cells. Myeloablative therapies, such as high-dose melphalan, should definitely be considered as a treatment option for AL amyloidosis, irrespective of the type of precursor immunoglobulin.