A unusual case of periampullary duodenal diverticulum causing obstructive jaundice. Duodenal diverticula are detected in up to 27% of patients undergoing upper gastrointestinal endoscopy with periampullary diverticula (PAD) being the most common type. Although periampullary diverticula rarely cause obstructive jaundice when choledocholithiasis or tumor is not present. The periampullary duodenal diverticulum causing extrinsic compression of common bile duct and obstructive jaundice is called Lemmel’s syndrome. An 58-yr-old woman came to the emergency room with obstructive jaundice and cholangitis. Abdominal CT scan revealed PAD compressing distal CBD with CBD dilatation. PAD shows signs of inflammation in CT scan and Endoscopy. Recognition of this condition is important since misdiagnosis could lead to mismanagement and therapeutic delay. Whenever PAD is present it should always be included as one of the differential diagnosis of obstructive jaundice.