We observed 22 cases of acute renal failure in children who were admitted to Severance Hospital from Jan. 1978 till Dec. 1980 and the results are as follows. The acute renal failure was the highest incidence between the age of 6 and 10 years (10 cases out of all), most of whom had acute glomerulonephritis and male was 3.4 times as high as in female. The causes of acute renal failure were renal origin(13 cases) and prerenal origin(8 cases) and in type of diseases the acute post streptococcal glomerulonephritis was the most frequent cause(8 cases). Average duration of oliguria or anuria was 3.4days(range 1~20 days), mean value of peak BUN level was 104mg/dl(range 54-184mg/dl) and it took average 5.6days(range 3~10days) to recover. Two patients died and those who died or discharge against advice were considered as died, mortality rate was 27%. It was remarkable that two neonates who were performed peritoneal dialysis on the 6 th day and the 7 th day after birth respecively were recovered from acute renal failure. Acute renal failure in children has more favorable outcome than in adult therefore early diagnosis and prompt treatment of conservative treatment and peritoneal dialysis should be performed.