Parvovirus B19(PV B19) is a nonenveloped single-stranded DNA virus that causes a wide variety of diseases ranging from benign childhood infection such as slapped-cheek rash(fifth disease) to life threatening diseases such as hydrous fetalis in fetuses or aplastic anemic crises in patients with hemolytic anemia. In immunocompromised hosts including organ transplant recipients, this infection can cause chronic anemia. Recently, the reports of cases of PV B19 infection have been increasing in transplant recipients and most reported cases of PV B19 infection-associated anemia in renal transplant recipients were successfully treated with intravenous immunoglobulin infusion. We experienced two cases of aplastic anemia caused by PV B19 infection in pediatric renal transplant recipients. The patients were an 8 year-old boy and 12-year-old boy who received allograft kidneys from their mothers. Anemia developed 2 weeks after transplantation and their serum was positive for PV B19 PCR. They were treated with 400 mg/kg of intravenous immunoglobulin(IVIG) for 5 consecutive days. In one of the case, anemia was corrected promptly after the first 5-day course of IVIG therapy but in the other, anemia persisted but responded to the second course of IVIG therapy. One year later, the patients have normal hematocrit levels and stable renal function These are the first cases of PV B19 infection treated successfully with IVIG in pediatric renal transplant recipients in Korea. (J Korean Soc Pediatr Nephrol 2005;9:275-281)