INTRODUCTION: “Windsock” or intraluminal duodenal diverticulum (IDD) is a rare congenital abnormality caused by an improper luminal recanalization of the foregut during embryological development. Most patients are asymptomatic. We present a case of recurrent pancreatitis and gastric outlet obstruction (GOO) caused by IDD in a young man with chronic alcohol use. CASE DESCRIPTION/METHODS: A 30-year-old man presented with severe nausea, vomiting and abdominal pain and found to have a third episode of acute pancreatitis in one month. Medical history was notable for alcohol abuse. However the patient stated that his last drink was more than a month ago. Lipase on admission was 130 U/L and he was found to have acute kidney injury (AKI) with creatinine 4.1 mg/dL. Magnetic resonance imaging without contrast revealed severe gastroduodenal obstruction and acute pancreatitis with pancreatic head pseudocysts. Esophagogastroduodenoscopy revealed nearly complete obstruction of the second portion of duodenum that the scope could not traverse. The patient was managed for acute pancreatitis, resulting most likely from paraduodenal pancreatitis causing GOO. After 10 days of aggressive treatment, the patient's pancreatitis has clinically much improved with better relief of the abdominal pain and resolution of the AKI. However he remained obstructed as large volume was drained from the nasogastric tube. A subsequent abdomen and pelvis computed tomography (CT) revealed interval decrease of the cluster pseudocysts previously seen by the pancreatic head but showed a “windsock” duodenal diverticulum. With conservative management, parental nutrition, intravenous fluids and pain control, the patient was able to tolerate frequent small portions of regular diet on hospital day 23. He was then discharged for elective surgery and resection of the IDD. DISCUSSION: Patients with IDD may present with chronic non-specific symptoms such as epigastric pain, nausea, vomiting, post-prandial fullness or rarely acute complications such as obstruction, hemorrhage, or pancreatitis. Radiologic diagnosis by CT or upper gastrointestinal series shows a typical “windsock” appearance hence the name. Endoscopic diagnosis may be challenging as the diverticulum can collapse and be unnoticed, or be mistaken for a polyp or a mass. Surgery has been the mainstay of treatment. However endoscopic techniques have been described in recent literature. IDD should be considered in the context of unexplained duodenal obstruction or recurrent pancreatitis.