In primary macroglobulinemia, IgM with a molecular weigth of one million daltons is abnormally elevated, and 80% of it is distributed intravascularly. This disease therefore results in multiorgan failure due to hyperviscosity syndrome which is caused by the elevated serum protein concentration and viscosity. In this report, we present one case of anemia and heart failure which could not be controlled by chemotherapy, but which took a good clinical course for 3.5 years through the use of maintenance double filtration plasmapheresis every two weeks.The patient was a male aged 56 years. The double filtration plasmapheresis was begun in September 1982, and continued until January 1986.By albumin supplementary double filtration plasmapheresis, we were able to decrease the serum IgM level from 9, 000mg/dl to 5, 500mg/dl, so that we were able to improve the RBC count (2.2 million/mm3 before lasmapheresis, increased to 3.3 million/mm3 thereafter), the platelet count (5.1×103/mm3 to 100×103/mm3), hemoglobin level (6g/dl to 10g/dl), and the CTR in chest x-p (68% to 65%) with the reduction of pulmonary congestion. Since August 1984, we have been able to obtain good results without albumin supply by the reverse lavage method. Even by this method we have been able to control the heart failure, and improve he ischemic ST change in ECG with slight progression of anemia.We applied maintenance double filtration plasmapheresis for a total of 95 times for 3.5 yearsfor this patient with multiorgan failure complicating primary macroglobulinemia, and it was shown to be both safe and useful.