During 1977 and 1991, 54 patients with lung cancer underwent surgery at Niigata University Hospital and were diagnosed with pathological T4. The survival rate of these pT4 patients was 32.5% at 3 years and 24.4% at 5 years. There was no significant difference between the survival rates of those with squamous cell carcinoma and those with adenocarcinoma. 5-year survival rate of 20 patients with N0 disease and 23 patients with N2 disease was 43.0% and 13.0%, respectively (p < 0.05). 5-year survival rate of 21 patients with organ invasion alone, 21 with dissemination or malignant effusion alone, and 12 with organ invasion plus dissemination or malignant effusion was 22.5%, 28.6% and 0%, respectively; there was no significant differences between these rates. Seven patients survived over 5 years; however, there were no obvious common factors. An aggressive surgical approach is indicated for T4 lung cancer, not only in patients with N0 disease but also in those with organ invasion alone or small amounts of malignant effusion alone.