Chylous fistula is a complication related to thoracic duct injury, appearing in upper abdominal, thoracic and neck surgery. Occurrence of chylous fistula is very rare after modified radical mastectomy. We encountered a chylous fistula case after breast cancer surgery and successfully treated it conservatively. It is important that all surgeons dealing with breast surgery should be aware that, altough rarely, a chylous fistula can develop after axillary dissection. Experience related to the occurrence of this complication and its management when it occurs is quite restricted.