A retrospective study was made of 480 Chinese patients with proven bronchogenic carcinoma, the top cancer in Hong Kong. The male-to-female sex ratio was low (1.9:1) and the female mortality rate ranked amongst the world's highest. The four major histologic types accounted for 87% of the cases: 39% epidermoid, 12% small cell anaplastic, 29% adenocarcinoma, and 7% large cell anaplastic. History of smoking was associated with epidermoid and small cell anaplastic carcinoma only. The commonest symptoms were anorexia and malaise (67%) and cough (51%). Overall our patients presented late and only 30 (6%) had curative surgery. The relatively rare occurrence of deep vein thrombosis (0.7%) is in keeping with the known low incidence of venous thrombosis in Chinese. Adenocarcinoma was a distinct group characterized by its preponderance in females (43%), lack of association with smoking habit (61% female cases being nonsmokers), high frequency of neurologic manifestation (21%) and clinical, roentgenographic, and bronchoscopic features of a predominantly centrally situated tumor. Possible etiologic factors for the high and still increasing incidence of adenocarcinoma are discussed.