From Nov. 1980 to Jun. 1987, 270 primary lung cancer patients were operated on at the department of Thoracic & Cardiovascular Surgery, Seoul National University Hospital. There Were 223 males & 47 females with 55.5 years of mean age. There were 151 [55.9%] squamous cell ca., 43 [18.8%] adenoca., 8 [3.5%] undiff. large cell, 9 [3.9%] undiff. small cell ca. & 18 [7.9%] mixed type, and also composed of 65 [28.3%] stage I, 31 [13.5%] stage II and 133 [58.1%] of stage III cases. They received 78 [34.1%] lobectomies, 62 [27.1%] pneumonectomies and 60 [26.2%] exploratory thoracotomies with 70% resectability rate. The five year actuarial survival rate of all patients was 37%. According to TNM stage, five year survival rate of the patients in stage I was 71%, those of stage II was 29% and of stage III 21%. According to histological cell type, five year actuarial survival rate of the squamous cell ca. was 35%, of adenoca. 49%, of undiff. large cell. 22%, 2 year survival rate of undiff. small cell was 31% and 3 year survival rate of mixed type was 47%. Hospital death was 2 case with a 1.3% early postop. mortality rate.