The hemolytic uremic syndrome is characterized by hemolytic anemia, thrombocytopenia and acute renal failure with the prodrome of acute gastroenteritis or upper respiratory infection. It usually occurs in children less than 4 years of age and is known as the major cause of acute renal failure in children. But few reports are available on etiology, clinical manifestation, progression and the outcome of the disease in Korea. Thus we investigated the patinests who had admitted and were diagnosed as hemolytic uremic syndrome during last 19 years. The male to female ratio is 2.5: 1 and the 9 of these patients were children. The etiologic diseases were acute gastroenteritis in 10 patients, upper respiratory infection in 1 patient, and 3 patients with drug related. The diagnosis was established by typical clinical and laboratory findings. The treatment were conservative in 2 patients, peritoneal dialysis in 8 patients, plasma- pheresis in 1 patient, hemodialysis and plasmapheresis in 2 patients and peritoneal dialysis and hemodialysis in 1 patient. The overall mortality rate was 36%' 3 patients died from sudden unexplained death, 1 patient from central nervous system complication and 1 patient from sepsis. There is a difference in children and adult in etiologic factors, but there are no difference in clinical mani- festations and laboratory findings. Intensive care with close observation and early dialysis is essential for patients survival.