A chylous fistula after a modified radical mastectomy is a rare occurrence; however, major anatomical variations in the termination of the thoracic duct may occur, rendering it susceptible to injury. High output chylous fistulae are difficult to manage and have local, metabolic, and immunologic complications with a mortality rate varying from 12.5-50%. Herein such a case of postmastectomy chylous fistula and its management are discussed. A 56-year-old postmenopausal woman with invasive duct carcinoma of the left breast underwent modified radical mastectomy with complete axillary clearance (Level I, II, III nodes). The operative procedure was uneventful. On the commencement of a normal diet, however, the patient started exuding milky fluid from the axillary drain and analysis of the fluid revealed biochemical features compatible with chyle. After 2 weeks of failed conservative management, the axilla was re-explored. A continuous flow of clear fluid was observed originating from a single major lymphatic trunk inferior to the axillary vein in the region of the former Level II nodes. The leak was controlled by the application of multiple mass ligatures using 2-0 silk suture. A part of the pectoralis major muscle was rotated and sutured over the area of the leak as additional reinforcement. Suturing a muscle flap over the leak has been described previously and functions theoretically by causing fibrosis. The chylous fistula in the present case was managed successfully with mass ligatures and muscle flap reinforcement.