The mediastinoscopy was a well known useful diagnostic tool for detection of certain mediastinal tumors ,mediastinal lymph nodes invasion by bronchogenic carcinoma and metastatic cancer. A total of 33 cases of mediastinoscopies were reviewed, which were experienced at Chon Buk National University Hospital from August,1980 to October 1991. Mediastinoscopy was performed through anterior or parasternal approach in 18 cases, cervical approach in 14 cases and both in 1 case. In 12 cases which were used for preoperative stagig of lung cancer, 10 cases[83.3%] had the positive biopsy results at mediastinal nodes. In 11 cases for diagnosis of lymph nodes and masses with unknown lung lesion, small cell carcinoma revealed in 3 cases,squamous cell carcinoma in 2 , adenocarcinoma in 1 case and the others were had the negative biopsy results. In 10 cases for diagnosis of mediastinal tumors, lymphoma revealed in 2 cases, malignant thymoma in 2, sarcoidosis in 2, tuberculous granuloma in 1, mesothelioma in 1, metastatic cancer with unknown origin in 1 case. Thoracotomy was performed in 3 cases of lung cancers, 2 patients with negative biopsy results in preoperative staging and 1 patient with subcarinal lymph node involvement only. Bleeding complications during mediastinoscopy were developed in 2 cases, managed by anterior mini-thoracotomy.