A review of 869 cases of multiple myeloma seen at the Mayo Clinic from 1960 through 1971 revealed that 98% of patients were 40 years of age or older and that 61% of them were males. Inital findings were bone pain in 68% of patients, anemia in 62%, renal insufficiency in 55%, hypercalcemia in 30%, a palpable liver in 21%, and a palpable spleen in 5%. Proteinuria was noted in 88% and Bence Jones proteinuria was identified in 49%. Skeletal roentgenographic abnormalities were seen in 79%. Serum protein electrophoresis showed a spike in 76%, hypogammaglobulinemia in 9%, and minor or no abnormalities in 15%, and a globulin spike was seen 75% of the urinary electrophoretic patterns. Immunoelectrophoresis of the serum revealed a monoclonal heavy chain in 83% and a monoclonal light chain in the serum, in 8% (Bence Jones proteinemia). Three patients had no monoclonal protein in the serum or the urine ("nonsecretory"). Amyloidosis was found in 7% of the patients. Follow-up information was obtained in 99.7% ; 82% of the 869 patients have died. Infection and renal insufficiency were the most common specific causes of death. The median survival was 20 months; 66% of the patients were alive at 1 year and 18% at 5 years.