Hemolytic uremic syndrome (HUS) occurs rarely in adults and its clinical manifestations are not well studied in Korea. We analyzed data from 14 adult patients admitted from 1987 to 1996 who fulfilled three criteria (Coombs negative microangiopathic hemolytic anemia, no artificial heart valve, and creatinine level>1.4mg/dL). No patient died, 3 patients needed dialysis for ESRD at first episode, 2 patients developed CRF, 1 patient had recurrence and progressed to ESRD at the second episode. 7 patients completely recovered their renal function without proteinuria nor hypertension. HUS secondary to other disease had the worst renal survival and patients with colitis had better renal survival. Patient age, sex, platelet counts, white blood cell counts, hemoglobin level, treatment modalities were not significantly associated with renal survival.