Background and objective To determine the value of mediastinoscopy in the mediastinal staging of lung cancer with clinical N2 disease. Methods We retrospectively reviewed 87 patients received mediastinoscopy for known or suspected lung cancer, including 83 cervical mediastinoscopies and 4 parasternal mediastinoscopies. All patients were staged clinical N2 for enlarged ipsilateral mediastinal and/or subcarinal lymph nodes (short axis > 1.0 cm)on computed tomography scan. Results Of the 87 patients, 61 cases proved N2 disease on mediastinoscopy. The other 26 mediastinoscopy-negative patients underwent thoracotomy for lung resection and mediastinal lymph node dissection in the same operative session. Final pathologic N staging were consistent for mediastinoscopic sampling and surgical dissection in 24 patients. N2 disease was found in 2 patients (false-negative of mediastinoscopy). The sensitivity, specificity, and accuracy of mediastinoscopy were 96.8%, 100%, and 97.7%, respectively. There was no mortality and only 1 complication(1.1%) for all 87 mediastinoscopic procedures. Conclusion Mediastinoscopy is a highly effective and safe procedure for the mediastinal staging of lung cancer with clinical N2 disease.