In 2007, the International Association for the Study of Lung Cancer proposed changes to the sixth edition of the lung cancer stage classification system, which were adopted by the Union Internationale Contre le Cancer in 2009 (TNM-7). Using historic patient data, the effects of reclassification from the TNM-6 to the TNM-7 system were researched within a single institution. We retrospectively reclassified the pathological records of 145 patients who underwent bronchoplastic resection for non-small cell lung cancer between 1991 and 2004, by applying the new TNM-7 classification for lung cancer. A comparison between the previous and the new system was conducted. Out of 145 patients, 49 (33.8%) were reclassified into a new stage, 42 (85.7% of reclassified cases) being allocated to a lower and seven (14.3%) being assigned to a higher stage. Most of the patients switched from stage IIB to IIA (n=31, 63.3%). The application of the new TNM-7 staging system resulted in a more accurate stratification of five-year survival curves. The newly revised TNM classification for lung cancer appears to be superior in defining different prognostic groups for this cohort and should lead to an improvement in stage specific tumor therapy.