We reviewed 124 patients from 1982 to 1988 who had a resected primary non-small cell lung cancer metastatic to mediastinal (N2) lymph nodes and a preoperative assessment of the mediastinum with computed tomography of the chest. Sixty-three patients studied had computed tomographic evidence of mediastinal lymph node enlargement. In these patients the survival at 5 years was only 6.6%, compared with the 5-year survival of 13.5% in 61 patients in whom the mediastinum was normal. Plain chest roentgenography with evidence of mediastinal adenopathy did not predict a poorer outcome. In addition, patients with tumors located in the left upper lobe were found to have an improved survival. These patients had a 5-year survival of 20.8%. Tumor histology, central location of the tumor, extranodal extension, and type of resection did not result in a significant survival difference.