Renal cell carcinoma is a common renal malignancy in adults but it is extremely rare in children. An 8-year-old boy visited our hospital with the complaint of right abdominal palpable mass. Computed tomographic (CT) scan revealed a right renal multilocular cystic mass which displaced the normal renal parenchyma. A right radical nephrectomy was done and pathological findings revealed cystic renal cell carcinoma. He received postoperative therapy with the administration of alpha interferon and has been well with no evidence of recurrence nor metastasis during 8 months after surgery. To our knowledge this is the youngest case of cystic renal cell carcinoma reported.