Background: Descending necrotizing mediastinitis(DNM) is a serious complication originating in odontogenic or oropharyngeal infection with previously reported mortality rates of 25% to 40%. We retrospectively reviewed the 4 years of our surgical drainage and debridement in DNM. Material and Method: We studied 7 cases diagnosed as DNM from 1997 through 2000. Primary oropharyngeal infection lead to DNM in four cases(57%) and odontogenic abscess in three cases(43%). All patients were received emergent cervicotomy and thoracotomy or sternotomy for debridement of necrotic tissue and mediastinal or pleural drainage. Result: Five cases were evolved well and were discharged after a mean of 42 days. Two patients(28.6%) died. Three patients required reoperation due to local surgical complication; empyema(two) and impending cardiac tamponade. One of these patients died on 12 post-reoperative day due to great vessel erosion, renal and respiratory insufficiency. The other patient died of broncho- esophageal fistula and asphyxia on 10 postoperative day without reoperation. Conclusion: On the basis of experience accrued in treating these patients, early diagnosis by cervicothoracic computed tomographic scan of neck and thorax aids in rapid indication of a surgical approach of DNM. We emphasize that performing early surgical drainage and debridement of necrotic tissues with intensive postoperative care can significantly reduce the mortality rate.