The expression of blood group-related antigens, A, B, H type 2, Lewis type 1 (Lewis(a) [Le(a)] and Lewis(b) [Le(b)]), Lewis type 2 (Lewis(x) [Le(x)] and Lewis(y) [Le(y)]), sialylated Le(a) (CA19-9), and sialylated Le(x) (CSLEX1), was analyzed sequentially with immunohistochemical methods in early gastric cancer, intestinal metaplasia, and uninvolved gastric mucosa obtained from 35 surgical specimens of patients who underwent gastrectomy. The high incidence of the inappropriate expression of Lewis type 1 antigens and the deletion of H and Lewis type 2 antigens was observed similarly in patients with cancer and intestinal metaplasia. The acquisition of CA19-9 and CSLEX1 and the deletion of B antigen frequently were found in intestinal-type cancer and all types of intestinal metaplasia. The simultaneous deletion of A antigen was detected only in the combination of intestinal-type cancer and incomplete-type intestinal metaplasia. Thus the present study shows that similar changes of tissue antigenicities exist in early gastric cancer and intestinal metaplasia.