The aim of this study was to present peroral cholangioscopic method, their technique, indications, contraindications, the advantages and disadvantages of this method. Peroral cholangioscopy is associated with ERCP and was developed in the last two decades by development of "mother & baby" endoscopic system. In same mode with percutaneous cholangioscopy or laparoscopic cholangioscopy, peroral cholangioscopy have an important role in diagnosis and therapy of common bile duct diseases. In 2001-2002 the authors have perform six peroral cholangioscopy for diagnosis and therapy (nonspecific radiological findings on ERCP) and in five cases, they have found choledochal lithiasis which was resolved by this way. In one case has not found any pathology. By their efficiency with a low rate of specific complications, peroral cholangioscopy is now an appropriate method in diagnosis and therapy of common bile duct disease.