Introduction: Many different factors are known to be able to cause an ileus. Case Report: A 72-year-old male underwent an endovascular procedure to treat his ruptured abdominal aneurysm. He developed a mechanical ileus five days after surgery. During re-operation an enormous retroperitoneal hematoma was revealed, causing the obstruction. Conclusion: Radiological re-evaluation can be useful and operative exploration must be considered in case of imminent perforation and/or after unsuccessful (conservative) therapy of an ileus. One should be aware that a retroperitoneal hematoma following a ruptured abdominal aneurysm can, in rare cases, cause a large bowel obstruction and therefore may need surgical intervention.