The present study was performed in order to investigate the correlation among the number of T zone histiocytes, the clinicopathologic parameters and the patient's survival. The subjects in this study were 131 advanced gastric carcinomas including 86 follow-up cases and 41 early gastric carcinomas. The infiltration of T zone histiocytes into tumor tissues was investigated using the immunohistochemical method with andti s-100 protein, nd the data obtained were evaluated statistically. T zone histiocytes were scattered among the cancer cells and in areas formed clusters within the cancer stroma. These cells were abundantly present in tumor tissues and around lymphoid follicles but were rarely seen in surrounding normal stomach tissue. Analysis of the number of T zone histiocytes showed no correlation between the number of T zone histiocytes and the clinicopathologic features except the degree of lymphocytic infiltration within the advanced and the early gastric carcinomas. Survival of the patients with a marked infiltration of T zone histiocytes in stage III was longer than that with mild infiltration of T zone histiocytes, but there was no statistical significance(P value=0.084). Multivariate regressio analysis revealed that the depth of invasion(P value=0.0074) and the lymphocytic infiltration(P value=0.0152) were the important prognostic factors. The results indicate that good prognosis is expected in cases with less deep invasion and high lymphocytic infiltration, and that the number of T zone histiocytes is in proportio to the degree of lymphocyte infiltration within the tumor, although not directly correlated with the patient's survival.