A new omental transposition technique was applied to a patient who underwent resection and in situ reconstruction of purulently infected abdominal aortic aneurysm to prevent recurrent retroperitoneal and graft infection. After wide separation from the transverse colon, the omental pedicle was transposed to the infrarenal retroperitoneal space through an opening of the transverse mesocolon to wrap the prosthetic graft and fill the infected space. The postoperative course was uneventful without any sign of recurrent infection in follow-up lasting 8 months. The authors' experience suggest that this 'transmesocolic' technique is an effective modality for critically ill patients with infected abdominal aorta.