ObjectiveTo evaluate the safety and efficacy of endoscopic retrograde cholangiopancreatography (ERCP) for patients with altered gastrointestinal anatomy. MethodsData of 108 patients who received 141 ERCP procedures were reviewed in this retrospective study from January 2013 to March 2018 in Beijing Friendship Hospital, and all patients had a history of gastrointestinal reconstruction. The patients were divided into the Billroth Ⅰ anastomosis group(n=33), the Billroth Ⅱ anastomosis group(n=74), the Roux-en-Y anastomosis group(n=32) and the Whipple group(n=2) according to the type of gastrointestinal anatomy. The success rate of reaching the papilla of Vater (POV)/anastomosis, deep biliary cannulation rate, clinical success rate, incidence of procedure-related complications and the total operation time were analyzed. ResultsIn 141 ERCP procedures after gastrointestinal reconstruction, the rate of reaching POV/anastomosis was 89.4% (126/141), and deep biliary cannulation rate was 85.7% (108/126). The clinical success rate was 75.2% (106/141) and the mean operation time was 38.5±23.5 minutes. Once the biliary cannulation was completed, the success rate of follow-up treatments significantly increased, reaching 98.1% (106/108). The success rates of reaching POV/anastomosis in the Billroth Ⅰ anastomosis group, the Billroth Ⅱ anastomosis group, the Roux-en-Y anastomosis group and the Whipple group were 100.0% (33/33), 87.8% (65/74), 84.4%(27/32) and 1/2, respectively, with significant difference (P=0.034). The operation times in these groups were 27.5±16.2 min, 40.6±23.2 min, 43.8±27.5 min and 59.5±12.0 min, respectively, with significant difference (P=0.011). There was no significant difference in the success rate of biliary cannulation or that of subsequent treatment operations（both P＞0.05）. The overall incidence of ERCP complications was 14.2% (20/141). The incidences of post-ERCP pancreatitis (PEP) and bleeding were 12.7% (18/141) and 1.4% (2/141), respectively. Operation time ＞30 minutes (P=0.024, OR=0.356, 95%CI: 0.152-1.278) was an independent risk factor of PEP after gastrointestinal reconstruction. ConclusionERCP is safe and feasible in patients with gastrointestinal reconstruction. Endoscopists should choose the best therapy to reduce incidence of adverse events in ERCP procedures.