It has been proven that there is no survival advantage of surgery in clinical N2 non-small-cell lung cancer rather than chemoradiotherapy. Several decades ago, the results of thoracic radiotherapy for Clinical Stage III non-small-cell lung cancer were poor, and long-term survival rate was only 6%. Recent advances in combined therapy (radiotherapy and chemotherapy) have improved median survival to 15–20 months. In the Japanese registry of lung cancer surgery, the number of patients with Clinical Stage IIIA has decreased over the last decade because of the poor results of surgery alone for Clinical Stage III non-small-cell lung cancer. In contrast, survival of patients with Clinical Stage III non-small-cell lung cancer treated with surgery has improved gradually. This can be mainly attributed to the following: first, well-selected patients are treated with surgery; second, improved diagnostic imaging has produced a ‘Will Rogers phenomenon’. Similarly, concurrent chemoradiotherapy has also further improved and in recent clinical trials, the median survival time was 28–40 months. Unfortunately, recent randomized trials comparing induction chemotherapy followed by surgery, or induction chemoradiotherapy followed by surgery with chemoradiotherapy showed no significant survival advantage of surgery. Until appropriate patient selection for surgery can be shown in randomized control trials, chemoradiotherapy is the mainstream treatment for clinical N2 non-small-cell lung cancer in clinical practice.