OBJECTIVE To emphasize the role of mediastinoscopy in the evaluation of mediastinal lymphadenopathy in postresection lung cancer patients. METHODS During the period 1997-1999, 11 patients who had a previous lobectomy or bilobectomy and mediastinal lymph node dissection for primary lung cancer underwent cervical mediastinoscopy for the evaluation and tissue diagnosis of mediastinal lymphadenopathy, discovered at planned, part of the follow-up,computed tomography (CT) of the chest. Five patients had received postoperative adjuvant radiation therapy and/or chemotherapy. RESULTS Nodal metastasis was histologically confirmed in 9 patients who subsequently received a combination of chemotherapy and radiation therapy, with a mean survival of 8.1 months. Two patients had no evidence of lymph node metastasis and remain alive and disease-free 21 and 27 months after mediastinoscopy, without any additional therapy. CONCLUSIONS Cervical mediastinoscopy, after a previously performed mediastinal lymph node dissection, is a special condition. However, it is the method of choice for the evaluation of the nature of mediastinal lymphadenopathy in postresection lung cancer patients. The alternative way of repeat thoracic CT at frequent intervals and the lymph node size enlargement criterion should be preserved for patients with a previous pneumonectomy or those who cannot tolerate additional radiation therapy or chemotherapy.