Mycotic aneurysm secondary to vertebral spondylitis is a rare but life-threatening pathology with high mortality and morbidity. The authors describe a successfully treated case of mycotic aneurysm of the common iliac artery complicated with vertebral spondylitis in a 74-year-old man. Under midline laparotomy, complete debridement of the infected tissues, in-situ replacement of the common iliac artery with cryopreserved aortic allograft, and iliac bone autotransplantation and omentopexy to fill the debrided cavity were performed. The postoperative course was uneventful, and he remains well 3 years after his operation without persistent infection or allograft rejection.