Chyloperitoneum is a rarely reported complication of abdominal aortic surgery. From 1981 to 1992, we treated 5 cases of chylous ascites after operations on the abdominal aorta and reviewed 22 previously published cases. There were 22 men and 5 women, with a mean age of 63.8 years (range: 27 to 93 years). Twenty cases (74.7%) occurred after abdominal aortic aneurysm resection, 5 (18.5%) after aorto-femoral bypass for occlusive disease, and 2 (6.8%) after resection of infected aortic grafts, 1 for occlusive disease and the other for infrarenal aortic aneurysm. Abdominal distention was the most common presenting symptom, occurring in 26 (96.3%) of 27 patients. The mean time from aortic operation to the development of symptoms was 18.5 days (range: 7 to 120 days). Diagnosis was confirmed by paracentesis, which yielded lipemic, sterile fluid in all patients. Therapeutic paracentesis was not successful when used alone, but, when combined with a medium-chain triglyceride (MCT) diet or total parenteral nutrition (TPN), it resulted in resolution of chyloperitoneum in 8 of 14 patients (57.2%). TPN alone or with paracenteses and/or diuretics was successful in 9 of 15 (60%) patients. Peritoneovenous shunts resolved chylous ascites in four of five patients not responding to diet and/or TPN but resulted in one death due to sepsis. Operative ligation of the injured lymphatic channel was successful in all five patients treated by laparotomy when nonoperative efforts failed. Chyloperitoneum resolved in all but two (7.7%) patients. There were five (18.5%) deaths, but only three (11.5%) were directly related to chylous ascites. Treatment with TPN resolved chyloperitoneum in all five of our own patients. We reached the following conclusions: (1) Chyloperitoneum is a rare complication of aortic surgery; (2) This disorder should be considered whenever persistent abdominal distention appears after aortic surgery; (3) The diagnosis is easily confirmed by paracentesis; and (4) Surgery to close the lymph fistula should be reserved for those patients in whom conservative therapy with MCT diets or TPN has failed.