Escretory urography defines the collecting system and shape of the kidneys. Radioisotope scanning complementsthis procedure, as it assesses the mass of proximal convoluted tubules. The close correltaion of the two techniqueleads to improved diagnostic accuracy. The renal scan with neohydrin and excretory urography of 100 cases wereperformed at the same time in renal disease at the Severance Hospital. Proof of diagnosis was based upon renalangiography, biopsy, operation, or spcial laboratory tests decisive for diagnosis. The results obtained were asfollows; 1. In patient with proven intrinsic masses, the scan has been confirmatory but non-specific, The scan canbe helpful when excretory urograms show no abnormality in patients of renal hematoma or renal carbuncle. 2. Renalscan with Hg-203 neohydrin is a good technique for detecting functioning renal tissue that is not apparent onexcretory urograms. And it is good for preoperative screeing test. 3. In renal failure, interpretation of rightkidney is confused due to increased concentration of radioactivity of the liver in scintillation scanning withHg-203 neohydrin. 4. The scintiscan has also been additional aid in establishing the diagnosis of congenitalanomaly such as polycytic kidney, horse-shoe kidney, hypoplasia, and agenes of kidney.