We report a 58-year-old male treated with surgical drainage by mediansternotomy using a pedicled omental flap for descending necrotizing mediastinitis (DNM). The patient recovered from DNM after five months of mechanical respiratory support. In deciding upon the most appropriate surgical approach for mediastinal drainage, the level of infection is a good landmark and should be investigated by CT scan. We also review the 43 cases of successful surgical treatment of DNM reported since 1989 in Japan, including our own patient, who were diagnosed with DNM by CT scan according to the classification proposed by Endo et al., and discuss the most appropriate surgical approach for mediastinitis based on the literature. In the treatment of DNM localized to the upper mediastinal space above the carina, a transcervical approach may be appropriate. In diffuse DNM extending into the lower anterior mediastinum, a mediansternotomy or a thoracotomy may be useful, and in diffuse DNM extending into both the anterior and posterior lower mediastinum, a thoracotomy may be the best approach for debridement of the lower posterior mediastinum, in addition to early complete debridement of the entire cervical area.