Stem cell transplantation has been incorporated in the treatment of primary systemic amyloidosis for 5 years. Results reported to date suggest that the response rates are substantially better than those for patients treated with low-dose traditional melphalan and prednisone chemotherapy. Unexpectedly high mortality rates have, however, been reported with stem cell transplantation, reaching 40% in some series. This unexpectedly high mortality appears to be related to multiorgan failure of tissues infiltrated with amyloid deposits. Deaths have been reported from gastrointestinal tract hemorrhage, gastrointestinal tract perforation, sudden cardiac death, and renal failure. The best patient for transplantation appears to have single organ involvement, an age <55 years, the absence of renal insufficiency, and no symptomatic cardiac dysfunction. Patients eligible to receive stem cell transplant represent a highly selected population, and before conclusions about the efficacy of transplantation are drawn, comparison with a matched control group is necessary. Amyloidosis should be considered an indication for stem cell transplantation in the context of a clinical trial so that results can be compiled and reported for an accurate assessment of response rate, survival, relapse rates and treatment-related toxicities. Bone Marrow Transplantation (2000) 25, 465-470.