Differential diagnosis of distinguishing between extrahepatic and intrahepatic biliary obstruction is very important because of surgical correction within the first 4 weeks of life is mandatory in isolated atresia of the extrahepatic bile ducts if irreversible changes in the parenchyme are to be avoided. The conventional liver function tests are little use in this respect and punch biopsy of liver is not without harzard. The radioactive Rose Bengal scanning and detection of fecal excretion are best method for differential diagnosis of infantile jaundice. In Yonsei University, We report 7 cases of infantile jaundice which were diagnosed by I-131 Rose Bengal liver and abdominal scanning with confirming by operation or liver biopsy. Case 1. : Non-excretion of I-131 Rose Bengal into the intestinal tract until 72 hours after IV injection and was diagnosed for Congenital Biliary Atresia by operation. Case 2. : Small excretion of I-131 Rose Bengal into the intestinal tract until 4 hours after IVinjection and was diagnosed for Choledochal Cyst by operation. Case 3. : Non-excretion of I-131 Rose Bengal into the intestinal tract until 48 hours after IV injection and was diagnosed for Congenital Biliary Atresia by operation. Case 4. : Non-excretion of I-131 Rose Bengal into the intestinal tract until 72 hours after IV injection and was diagnosed for Neonatal Hepatitis with Bile Stasis by liver biopsy. Case 5. : Non-excretion of I-131 Rose Bengal into the intestinal tract until 48 hours after IV injection and was impressed for complete obstruction of biliary tree on I-131 Rose Bengal scanning. Case 6. : Small excretion of I-131 Rose Bengal into the intestinal tract on 48 hours abdominal scanning and was impressed for partial obstruction of biliary tree on I-131 Rose Bengal scanning. Case 7. : Small excretion ofI-131 Rose Bengal into the intestinal tract on 48 hours abdominal scanning and was impressed for partial obstruction of biliary tree on I-131 Rose B ngal scanning.