The gastrointestinal tract is the largest organ in our body and comprises the major frontier against the ravages of the outer world. The gastrointestinal tract and liver play important roles not only in the absorption of nutrition but also in controlling the immunity and endocrine functions. Our center provides medical services covering a wide range of diseases in the field of gastroenterology and hepatology, that is, anatomical disorders, inflammatory diseases, neoplasitc diseases, immunological diseases, and endocrine diseases. Division of gastroenterology provides various endoscopic services including endoscopic diagnosis, evaluation, and treatment of gastrointestinal tract diseases with up-to-date endoscopic facility being equipped with the cutting-edge endoscopies, endoscopic ultrasonography, and capsule endoscopy. Endoscopic submucosal dissection of early gastric and colon cancer is actively performed with high safety. Especially, our center has the system to give endoscopic hemostasis of gastrointestinal tract bleeding within a few hours of patients' arrival. Division of hepatology provides comprehensive and specified services including intensive care of patients with primary liver cancers, liver cirrhosis and its complications, acute/chronic hepatitis, hepatic failure, and alcoholic and non-alcoholic fatty liver diseases. Among the options for the treatment of hepatocellular carcinoma, surgical resection, radiofrequency ablation, transarterial chemoembolization, systemic chemotherapy, and radiation therapy including tomotherapy are available. With the combination of these treatment modalities, outstanding results with minimal complications are being obtained. Division of pancreatobiliary diseases performs many kinds of special diagnostic studies including endoscopic retrograde cholangiopancreatography, endoscopic ultrasonography and aspiration cytology, and cholangioscopy. As a therapeutic procedure, stent placement, endoscopic biliary or pancreatic sphincterotomy, removal of the bile duct or pancreatic duct stones, endoscopic biliary drainage, extracorporeal shock-wave lithotripsy, and electrohydraulic lithotripsy are being commonly employed with high success rate. Academically, major and remarkable research programs have been carried out in the areas of Helicobacter pylori associated diseases, acid related diseases, esophageal reflux disease, inflammatory bowel diseases, gastrointestinal neoplastic diseases, viral hepatitis, liver cirrhosis, and hepatocellular carcinoma. As a result, a number of papers have been published in many renowned SCI journals.