A total of 805 intra-oral neoplasms was diagnosed in Chinese subjects from 1964-1982 in the University Department of Pathology, Hong Kong. Squamous cell carcinoma (SCC) totalled 502 and constituted 86% of 582 malignant tumors. Although the majority (82%) of SCC were of the well-differentiated type, the relatively poor differentiation exhibited by palatal SCC in the females, was noteworthy. There was a marked male predominance in all SCC subgrouped by anatomic site, but the sex difference declined after the 6th decade and disappeared by the 9th decade. A significant rise in the incidence rate was observed in the decade after 1973 compared to that for 1964-72 in both male (p less than 0.0001) and female (p less than 0.001). It is speculated that, in the absence of improved oral hygiene and dental care, changes in the smoking and drinking habits in the local Chinese are of causal importance.