MULTIPLE myeloma is characterized by an increase of abnormal plasma cells in the bone marrow and monoclonal protein in the serum, often with osteolytic bone lesions. Its course is progressive: anemia, weakness, fatigue, fractures, bone pain, hypercalcemia, renal insufficiency, recurrent infections, bleeding, and deterioration lead to death. However, we have seen six patients with illnesses that met the criteria for the diagnosis of multiple myeloma¹ but have not had a progressive course. Although no chemotherapy was given, their condition has remained stable for five or more years. We designate these cases as "smoldering multiple myeloma." We wish to call attention . . .