Primitive aortic hydatidosis is exceptional. We report the case of a 55-year-old woman who had pain in her left lower limb for a week. A computed tomographic angiogram showed a multivesicular and fluid-density mass intimately contiguous to the descending thoracic aorta seen on an endoluminal subtraction image and hydatid cysts in the spleen. The surgical approach was through a thoracophrenolombotomy with right femorofemoral bypass. Complete resection of the destroyed aortic portion was performed, and continuity was restored by an aortoaortic bypass using a Dacron (INVISTA, Kennesaw, Georgia) prosthesis. Hydatid fragments were evacuated after thrombectomy of the left iliac artery. The surgical procedure was completed by a splenectomy. Postoperative follow-up was uneventful. After 6 months, computed tomographic angiography showed a patent bypass.