Ciliated metaplasia (CM) of gastric mucosa is common in Japanese individuals but rare in whites. We studied 36 consecutive gastrectomies from Chinese individuals for the presence of CM. The gastrectomies were performed for adenocarcinoma (n = 22), benign ulcer (n = 13), and malignant lymphoma (n = 1). Ciliated metaplasia was found in 16 (44.4%) of the stomachs, with equal distribution between male and female patients. Ciliated metaplasia was present in 11 cases (50%) of adenocarcinoma and in five cases (38.5%) of benign ulcer, the difference being statistically insignificant. Contrary to previous studies, there was no increased frequency of CM in gastric mucosa harboring an intestinal-type adenocarcinoma compared with those with non-intestinal-type tumors. Ciliated metaplasia always co-existed with intestinal metaplasia. Colonization by Helicobacter pylori was not associated with an increased incidence of CM. In five cases (22.7%) of adenocarcinoma ciliated tumor cells were found, and all of these cases showed CM in the gastric mucosa. In one of these cases the whole tumor was composed of glands formed by ciliated cells. In the other cases there was a morphologically different nonciliated component. The cilia in the tumor cells showed light microscopic and ultrastructural changes identical to those of the cilia seen in CM affecting the nonneoplastic gastric mucosa. This study documents for the first time the co-existence of CM and ciliated adenocarcinoma in the same stomach. It is concluded that in the Hong Kong Chinese population CM is commonly present in gastric mucosa harboring an adenocarcinoma or benign ulcer. Adenocarcinomas with ciliated cells are strongly associated with CM.