The prognosis for non-small cell lung cancer (NSCLC) with chest wall invasion can vary due to the heterogeneous nature of the cell population. Because NSCLC with large tumors (>7 cm) have been reclassified as T3, the applicability of the new designation must be evaluated. We reviewed 140 patients with chest wall T3 and 28 patients with T3 NSCLC with large tumors, but no chest wall invasion who underwent resection at our institution. Among chest wall T3 patients, elderly T3 patients (≥80 years old) who died within 42 months, patients with either lymph node or pulmonary metastasis, or patients with a large tumor (>7 cm) had poorer prognoses than those who had not. The survival rates for cases with chest wall T3 and cases with a large tumor without chest wall invasion were not significantly different. NSCLC patients with chest wall T3 with lymph node, or pulmonary metastasis, or with a large tumor should be considered for further multimodal treatment with or without resection to enhance their survival time. Elderly patients with chest wall invasion may not be good candidates for resection. A large tumor is so aggressive that re-classification of large tumor cases as T3 is suitable.