SummaryThe omental flap is often used to fill the space around the artificial vascular graft as a network sheet to prevent artificial vascular infection. In this study, we report a case in which the omental flap was divided into three parts to fill the dead spaces around the multiple-branched graft, as well as to wrap the suture lines of the graft after graft replacement in a patient with an infected thoracic aorta.An 88-year-old woman was admitted to the hospital with fever and impaired consciousness. Computer tomography revealed an aortic arch aneurysm with enlargement. After emergency stent–graft interpolation and antibiotic treatment, an infected thoracic aortic aneurysm was removed, and a multiple-branched graft replacement of the upper arch was performed. After harvesting an omental flap based on the right gastroepiploic vessels, the omental flap was divided into three on the basis of the epiploic vessels. The middle part of the omental flap was used to fill the space around the lesser curvature of the arch and the distal anastomotic site, the accessory part was used to fill the space between the ascending aorta and the superior caval vein, and the right part was used to wrap the three cervical branches, separately. Fifteen months after surgery, the patient had recovered enough to resume work without any signs of inflammation.