From May 1978 to Sep. 1990, 106 patients who had been diagnosed as primary lung cancer and operated on at the Department of Thoracic & Cardiovascular Surgery, Han Yang University, were clinically evaluated. 1. The peak incidence of age was 5th decade of life[37.7%] and 6th decade[29.2%]. Male to female ratio was 3.8: l. 2. Most of symptoms were respiratory, which were cough, chest pain, hemoptysis, and asymptomatic cases were 2.9%. 3. Histopathologic classifications were squamous cell carcinoma[53.7%], adenocarcinoma [23.8%], bronchioloalveolar cell carcinoma[6.6%], undifferentiated large cell carcinoma[6.6%], small cell carcinoma[3.8%], adenosquamous carcinoma[3.8%] and others[1.8%]. 4. Methods of operation were pneumonectomy 49.1%[52cases], lobectomy 21%[22cases] bilobectomy[6cases], lobectomy with wedge resection[3cases], exploration 21.9%[23cases], and resectability was 78.3%. 5. Staging classifications were Stage I [22.6%], Stage II [11.3%], Stage IIIa[42.6%], Stage IIIb[21.7%] and Stage lV[1.6%]. Resectability by Stage; Stage I was 100%, II 100%, IIIa 84.4% and IIIb 30.4%. 6. Causes of most of inoperable cases were invasion of mediastinal structures and diffuse chest wall, and others were contralateral lymph node invasion and malignant pleural effusion. 7. Operative mortality was 6.7% which caused by arrhythmia, sepsis, pulmonary edema, and radiation pneumonitis. 8. On the long term follow up of the resectable cases, overall 1 year survival rate was 58.5 %, 2 year 39%, and 5 year 19.5%. Five year survival rate was 40% in Stage I, 25% in Stage II and 11.7% in Stage Illa. As for the method of operation, the higher 5 year survival rate was observed in lobectomies[33.3%] than in pneumonectomies[10.3%].