Mediastinoscopy is a significant procedure used in the diagnosis of mediastinal tumors in thoracic diseases. A special instrument is inserted into the mediastinum, the space between the heart and lungs. The procedure is performed through an incision in the patient's neck, progressing externally to the trachea to reach the mediastinum. A biopsy is then taken from this area. Mediastinoscopy is a reliable procedure alongside methods such as computed tomography and nuclear medicine. The procedure is performed under general anesthesia. Examination is performed using a mediastinoscope, a long, thin, flexible tube with a small camera. The specialist examines the structures in and around the middle of the chest. Images captured by the camera are recorded on a computer. Mediastinoscopy plays a significant role in determining treatment strategies for important conditions such as lung cancer, lymphoma, sarcoidosis, and mediastinal tumors. In recent times, alongside diagnostic methods such as PET, mediastinoscopy remains a gold standard method. Its morbidity and mortality rates are also low.