It is well known that small cell bronchogenic carcioma is frequently manifested as a lymph node enlargement and sometimes confused with other causes of lymph node enlargement such as lymphoma, tuberculous lymphadenopathy, and metastatic lymphadenopathy from other organs in plain chest toentgenogram alone. Therefore, the authers took it upon themselves to analyze the growth and metastatic patterns of small cell bronchogenic carcinoma as seen on the CT scan and thus find the points of difference with other causes of lymphadenopathy. The CT findings of 45 patients with small cell bronchogenic carcinoma showed that 33 cases(73.3%) had a central mass, 17 cases had a norrowing of the bronchus with lymph node enlargement, and 14 cases(31.1%) had an obstruction of the bronchus with atelectasis and lymph node enlargement. Forty-two patients(93.3%) showed lymph node enlargement. The subcarinal lymph node was the one most frequently enlarged(66.7%). The anterior mediastinal lymph node(20%) and pulmonary ligament lymph node(15.6%) were less frequently enlarged.