It seems that primary lung cancer is increasing in frequency and the problems presented by the carcinoma of the lung have been explored on many occasions in view of clinical and radiological aspects in Korea. However, no literary reports on a large series of radiological findings of bronchogenic carcinoma have been yet published. This presen study is mainly to analyse the radiological mainfestation of primary lung cancer by the cell type and also to observe the relationship of carcinoma of the lung to tuberculosis which is prevalent in Korea. Histologically proven 200 cases of lung cancer during the period of 8 years were reviewed with plain chest films, tomogram, bronchography and esophagography. The results are as follows: 1. Male to Female sex ratio was 3.8 : 1. Incidence was most common in 6th decade as 43%. 2. Cell types of primary lung cancer are as follow: Sq. cell ca. 45%, Undifferenciated Ca. 15% Oat cell ca. 22%, Adeno Ca. 17%, and Alveolar cell Ca. 3%. 3. The most c mmon radiological abnormality was the mass shadow in either hilum and/or peripheral lung field, and the next being atelectasis. Bulky nodal mass was most frequently seen in oat cell Ca. and the peripheral mass in adenocarcinoma. 4. No mass measured less than 2cm in size and most of them was over 6cm in mean diameter. 5. Solitary pulmonary nodule was seen in 10% and its man size was 5.8cm and had smooth, lobulated margin without calcification. 6. Mediastinal widening was the most frequent finding in oat cell ca. and undifferenciated carcinoma. Aden ocarcinoma showed peripherally located mass with frequent chest wall invasion as comparied with other cell type. Alveolar carcinoma showed characteristic small nodular or granular infiltration without hilar node enlargment. 7. Cavitary carcinoma of the lung was 4 cases (2%) and all had relative thick wall and 2 showed fluid level. 8. Other minor findings include obstructive paeumonitis and lymphangitic metastasis and pleural effusion. 9. Co xistence of pulmonary tuberculesis and lung cancer was 37 cases (18.5%), of which 20 cases had developed lung cancer in the same location with previous pulmonary tuberculosis while 17 cases in other location. 10. There was no occult lung cancer. Most of our cases were in late inoperable stage and early detection of lung cancer should be emphasized by means of intensive radiological and clinical approach.