This paper presents the pathological findings of small cell carcinoma of lung of 202 patients treated by surgery in our department from 1957 to 1984. Small cell lung cancer comprises 15.7% of all lung cancers. Gross type: central type was 67.3% and peripheral type was 32.7%. According to the histological classification system for lung tumor, WHO, 1981, small cell carcinoma is divided into three subtypes: (1) oat cell carcinoma (118 cases), (2) intermediate cell type (55 cases), and (3) mixed oat cell carcinoma (29 cases). Electronic microscope examination was done in 3 cases. Neurogenic secretory bodies in the cytoplasm were found in 2 oat cell carcinoma, but not in the other intermediate cell type. The 5-year survival rate of small cell carcinoma was 22.4% among whom four survived over ten years. The 5-year survival rate of oat cell carcinoma, intermediate cell type and mixed oat cell carcinoma were 19%, 34.8% and 9.1%, respectively. The intermediate cell type was the best in the 3 types. The 5-year survival rate of the peripheral type was 30.4% which was higher than that of the central type (18.9%). The 5-year survival rate was 30.8% in patients without metastasis to the lymph nodes in the hilus or mediastinum, and 18% in those with metastasis. There were no differences in the prognosis of those whether the pleura were involved or the resection stump was positive.