Background: The extent and the necessity of lymph node dissection has yet to be defined after resectional surgery for lung cancer. We aimed to analyze the lobe-specific extent of lymph node positivity in patients who underwent preoperative mediastinoscopy as a routine strategy. Methods: A total of 280 patients with non-small cell lung cancer with negative mediastinoscopy were operated on in our center between January 1997 and June 2003. Hilar and mediastinal lymphadenectomy was performed in every patient. Results: The most commonly involved lymph nodes were found to be paratracheal station lymph nodes (n = 83; 96.5%) for right upper lobe tumors, subcarinal station lymph nodes (n = 52; 88.1%) for right lower lobe carcinomas, aorticopulmonary lymph nodes (n = 62; 92.5%) for left upper lobe and subcarinal station lymph nodes (n = 49; 96.0%) for left lower lobe tumors. In the patients with right upper lobe, right lower lobe and left lower lobe tumors, the presence of a tumor at these stations was found to be an indicator for poor prognosis (p = 0.033, p = 0.0038 and p = 0.0016, respectively). Patients with multiple station N2 disease did not survive beyond 3 years. Conclusions: In patients who underwent routine mediastinoscopy, lobe-specific lymph node dissection could be recommended. Patients with multilevel N2 involvement did not seem to benefit from resectional surgery.