The value of a second remediastinoscopy in the diagnostic assessment of new or recurrent lung cancer have never been evaluated before. We retrospectively reviewed our experience with a third mediastinoscopy in the staging of lung cancer to define its role. In 13 patients a third mediastinoscopy was performed; in all cases the indication was suspected or proven new or recurrent lung cancer. All accessible lymph nodes were sampled. The technical aspects of the procedure are described. Nine patients with a negative third mediastinoscopy underwent subsequent surgery, four patients were not operated on, based on the positive histology and concomitant diseases. There were no major complications. Reremediastinoscopy can be performed safely and has proven to be helpful in defining potential surgical candidates. Mediastinal involvement can be excluded in most.