Major complications of endoscopic retrograde cholangiopancreatography (ERCP) include pancreatitis, hemorrhage, cholangitis, and duodenal perforation. The occurrence of free air in the peritoneal cavity post- ERCP is a rare event (< 1%), which is usually the result of duodenal or ductal perforation related to therapeutic ERCP with sphincterotomy. We describe for the first time a different aetiology of pneumoperitoneum, in an 84-year-old woman with pancreatic cancer and a large hepatic metastasis, after ERCP with common bile duct stent deployment. Our patient developed, pneumoperitoneum due to air leakage from rupture of intrahepatic bile ducts and Glisson’s capsule in the area of a peripheral large hepatic metastasis. The potential mechanism underlying this complication might be post- ERCP pneumobilia and increased pressure of intrahepatic bile ducts leading to rupture of intrahepatic bile ducts in the liver metastatic mass owing to neoplastic tissue friability. This case indicates the need for close clinical and radiological observation of patients with hepatic masses (primary or metastatic) subjected to ERCP. In such patients, avoidance of excessive air insufflation during ERCP and/or placement of a nasogastric tube for bowel decompression immediately after ERCP might be a reasonable strategy to prevent such unusual complications. Major complications of endoscopic retrograde cholangiopancreatography (ERCP) include pancreatitis, hemorrhage, cholangitis, and duodenal perforation. The occurrence of free air in the peritoneal cavity post- ERCP is a rare event (<1%), which is usually the result of duodenal or ductal perforation related to therapeutic ERCP with sphincterotomy. We describe for the first time a different aetiology of pneumoperitoneum, in an 84-year-old woman with pancreatic cancer and a large hepatic metastasis, after ERCP with common bile duct stent deployment. Our patient developed , pneumoperitoneum due to air leakage from rupture of intrahepatic bile ducts and Glisson’s capsule in the area of ​​a peripheral large hepatic metastasis. The potential mechanism underlying this complication might be post-ERCP pneumobilia and increased pressure of intrahepatic bile ducts leading to rupture of intrahepatic bile ducts in the liver metastatic mass owing to neoplastic tissue friability. This case indicates th e need for close clinical and radiological observation of patients with hepatic masses (primary or metastatic) subjected to ERCP. In such patients, avoidance of excessive air insufflation during ERCP and / or placement of a nasogastric tube for bowel decompression immediately after ERCP might be a reasonable strategy to prevent such unusual complications.