Spontaneous closure of a chylous fistula is usual, but the rare intractable fistula may lead to disastrous nutritional and immunological consequences. We report the surgical management of 5 patients with intractable fistulas with daily drainage averaging 2,060 ml. Conservative therapy failing, the 5 patients underwent 6 ligations of the thoracic duct. A limited posterolateral thoracotomy was used in 3, full right thoracotomy in 2, and left thoracotomy in 1. Ligations were carried out immediately above the diaphragm, and not at the fistula site, by a mass ligature technique encircling all tissue between the azygos vein and aorta. The ligation achieved immediate cessation of drainage in four of five initial procedures and in the fifth patient, at a second operation. High-output thoracic duct fistulas may be handled by supradiphragmatic ligation of the thoracic duct. Identification of the fistula site or the dissection of the thoracic duct itself is avoided by this technique.