Background <p>Diaphragmatic hernia following pericardial window is a rare complication, typically presenting in the early postoperative period. Delayed presentation with intrathoracic closed-loop small bowel obstruction is exceedingly uncommon (1,2).</p> Case presentation <p>A 74-year-old male presented with nausea, vomiting, abdominal distension, and epigastric pain two years after a subxiphoid pericardial window for recurrent pericardial effusion. Computed tomography demonstrated herniation of small bowel into the thoracic cavity through a diaphragmatic defect with features of closed-loop obstruction. The patient underwent urgent exploratory laparotomy, which confirmed viable small bowel herniated into the thoracic cavity. The bowel was reduced without resection, and the diaphragmatic defect was repaired using Gore-Tex mesh. The postoperative course was uneventful.</p> Conclusion <p>Delayed diaphragmatic hernia after pericardial window is a rare but potentially life-threatening complication. This case underscores the importance of maintaining a high index of suspicion in patients presenting with obstructive symptoms, even years after the initial procedure (3,4).</p>