Endoscopic retrograde cholangiopancreatography (ERCP) in post-gastrectomy patients with Billroth II (BII) reconstruction and Rouxen-Y (RY) reconstruction presents a challenge to therapeutic endoscopists. Major diffculties, including intubation to the ampulla ofVater, selective cannulation, and ampullary intervention, must be overcome in these patients. Recent data have shown that deviceassisted ERCP allows for high success rates in these patients because various devices are useful for overcoming major difficulties. Therefore, good knowledge of postoperative anatomy and various devices is mandatory before performing ERCP procedures for postgastrectomy patients.