Primitive neuroectodermal tumor (PNET) is relatively uncommon, arising outside the central nervous system. Very rarely, it occurs within the urinary system. A 55-year-old woman presented with gross hematuria and right flank pain which had begun two months earlier. A well-marginated, low-density mass containing high-density portions representing hemorrhage was seen in the right kidney at pre-enhanced CT; contrast enhancement was not prominent. At both T1- and T2- weighted MR imaging, a multilocular cystic mass with high signal intensity portions representing hemorrhage was observed. Contrast enhancement was absent. We report the radiologic findings in this case of renal PNET.