Gastrointestinal complications after aortic surgery are unusual; conse quently, their natural history has not been adequately defined. The authors reviewed 505 cases of aortic reconstruction done over a fourteen-year period in order to assess the clinical significance of postoperative gastrointestinal compli cations on outcome and to determine if there were preoperative or operative predictive factors for the development of such complications. There were 37 cases of gastrointestinal complications (7.3%). No significant difference was found between the complication rates after aneurysm resection versus aortic bypass for occlusive disease. Overall, the complication rates were: small bowel obstruction, 2.2%; gastrointestinal hemorrhage, 1.6%; small bowel ischemia, 1.2%; and colon ischemia, abdominal abscess, local trauma, pancreatitis, aor toenteric fistula and jaundice, each < 1%. More than one half of the complica tions occurred during the same hospitalization. Forty-three percent (16/37) were treated surgically, and these had a mortality of 44% (7/16) as opposed to 10% (2/21) for those with complications not requiring operation. Overall mor tality as a direct result of gastrointestinal complications was 24% (9/37) versus less than 5% for those patients not having such complications. Significant corre lation for gastrointestinal complications occurred with: emergency operation, and postoperatively, positive urine and blood culture, steroid administration, white blood cell count greater than 12,000, and creatinine greater than 1.5 (p < 0.05). When patients aged sixty or older were analyzed separately, signifi cant correlation was also found with ruptured aorta, emergency operation, inci dental GI operation, preoperative adhesions and postoperative fever (p < 0.05). Analysis by computerized logistic regression in this group showed that ruptured aorta, incidental GI operation, increased duration of surgery, higher age, and the use of bifurcation grafts were all of significance synergistically in the predic tion of gastrointestinal complications. The authors conclude the following: (1) The incidence of gastrointestinal complications after aortic surgery is low, but when these occur, the mortality is fivefold greater. (2) The occurrence of gastro intestinal complications may be predictable preoperatively in selected patients. (3) Those complications requiring operative intervention have a higher mortal ity.