Retroperitoneal and horseshoe abscesses are particularly important because of the anatomic characteristics and the clinical differences between treatment approaches. There are several challenges in treating perirectal and retroperitoneal abscess, the most important of which are partial recovery, high recurrence rates, and continence problems. A 65-yearold male patient underwent laparotomy at an external center with a diagnosis of ileus. Although no intraoperative pathology was detected, ileus persisted postoperatively, and the patient was referred to our clinic where he was diagnosed with a complicated horseshoe abscess, 9 cm in diameter and displaying retroperitoneal extension. Perirectal abscess drainage was performed, and the patient was discharged on the 5th day after the treatment. To the best of our knowledge, there have not been any previously reported cases of ileus caused by retroperitoneal abscess as a complication of horseshoe abscess. The case presented in this paper represents a rare complication, thereby contributing to the literature which remains to be explored.