The correlation between gallbladder stones (gallstones) and various gallbladder diseases was examined. The incidence of gallstones was 47.1% in cases of non-neoplastic epithelial polyp, 48.0% in adenoma, and 59.1% in adenocarcinoma. There was no relation between the incidence of gallstones and sex. The incidence of gallstones in cancer cases showed no difference among histological gradings. Non-neoplastic epithelial polyps, adenomas and carcinomas were divided into metaplastic type and non-metaplastic type based on the presence or absence of metaplastic changes. Comparison of the incidence of gallstones showed that cases of metaplastic-type polyp and adenoma had a higher incidence of gallstones than non-metaplastic-type polyp and adenoma. In the cases of cancer, no differences were observed in the incidence of gallstones between metaplastic-type and non-metaplastic-type carcinomas. However, comparison among early carcinomas showed that metaplastic-type carcinoma had a significantly higher incidence of gallstones than the non-metaplastic-type. These results suggest that gallstones may play an important role in the histogenesis of gallbladder diseases of the metaplastic type.