The goal of this study was to analyze the mortality data following neck dissection and determine the risk factors of early death. The hospital mortality records were analyzed from 3,015 consecutive patients who underwent neck dissection. A case control study analyzed risk factors of death during the first 3 postoperative days. The mortality incidences were 0.50% and 1.33%, respectively, during the first 3 and the first 30 postoperative days. Eleven of the 12 unexplained deaths occurred during the first 3 postoperative days, and most of these patients died suddenly. They were more likely to be alcoholic and to have undergone nerve section. In most of the patients who died after the third postoperative day, death was related to a postoperative complication. Although the mechanisms of sudden death remain unclear, careful follow-up of these patients during the early postoperative days should be performed to reduce the mortality risk by shortening the delay of care.