BACKGROUND Descending necrotizing mediastinitis (DNM) following an oropharyngeal infection is a rare disease with a rapid course and a mortality rate of up to 40%. The aim of this study, is to outline the diagnosis and the appropriate treatment of DNM. METHODS A retrospective study (1986-2007) of patients with DNM was made. Only patients with cervical cellulitis associated with DNM were included. RESULTS Eight men and two women with an average age of 43 years were treated. Five had diabetes. The average for diagnosis and treatment was eight days. In eight cases, we found a dental origin and in two cases a pharyngeal origin. The diagnosis of DNM was made thanks to cervico thoracic CT scan in six cases. In the others patients, they had at presentation clinical and radiological evidence of mediastinal diffusion. All patients were treated by broad spectrum antibiotherapy. All had cervical drainage. Mediastinal drainage was made by cervical approach in 2 two cases and via a right thoracotomy in eight cases. Eight patients died. CONCLUSIONS Odontogenic DNM is a rare disease with rapid course. Clinical diagnosis is difficult and early recognition with a low thresold for CT scanning is essential. CT is also useful for the treatment and in the post operative assessment. All affected tissue plane must be debrided. Surgical management and mediastinal drainage remain controversial about the indication of thoracotomy.