Descending necrotising mediastinitis is a severe infection spreading from the cervical region to the mediastinal connective tissue. It represents a virulent form of mediastinal infection, requiring prompt diagnosis and treatment to reduce the high mortality associated. An optimal debridement and drainage through an open thoracotomy access are the keys for a successful outcome. Two patients, males, 70 and 75-years-old with descending necrotising mediastinitis were treated in our Institution in April '05. One had an odontogenic abscess and the other had a retropharyngeal abscess. Operative procedures included thoracotomy with radical surgical debridement of the mediastinum and excision of necrotic tissue associated with transcervical surgical debridement and drainage. Postoperatively mediastinum-pleural and cervical irrigation with iodopovidone 2 per thousand was performed until a culture of pleural effusion become negative. Postoperatively both patients suffered from severe complication including septic shock and acute respiratory distress syndrome. The 70-years-old patient had an acute renal failure too. Postoperatively the length of the intensive care unit stay was 40 and 42 days, respectively. The outcome was favorable in both patients. Early detection and immediate open surgical treatment could be the best way to reduce morbidity and mortality rate. Descending Necrotising Mediastinitis cannot be adequately treated without mediastinal and cervical excision of necrotic tissue and drainage including an open thoracic and cervical approach.