Objective: To investigate the clinical significance of cell adhesive molecule (CD44) expression on periphery blood (PB) of patients with gastric cancer. Methods: Both the level of CD44 and the immunocyte phenotype of the lymphocytes of 110 patients with gastric cancer and 100 healthy subjects were examined by flow cytometry, and the results were analyzed pathologically and statistically. Results: The mean of the CD44% in PB of the healthy subjects was 46.14(13.4 and there were no statistic differences for their age and sex. Site of tumor growth: The significant difference (P<0.01) was present between the patients with the cardiac part (C) or body of gastric (M+C) cancer and normal individuals. The significant difference (P<0.05) was present between patients with the 3 sites involved gastric cancer and normal individuals. Type of tumor mass: The significant difference (P<0.05) was present between patients with mixed type gastric cancer and normal individuals. Size of tumor mass: The significant difference was present between the normal individuals and patients with gastric cancer > 10 cm mass (P<0.0l) and 7(10 cm mass (P<0.05). Degree of tumor differentiation: The significant difference (P<0.01) was present between the patients with low differentiation gastric cancer and normal individuals. The significant difference (P<0.01) was present between patients with metastatic stage: The significant difference (P<0.0l) was present lymph node gastric cancer and normal individuals. Clinical between the patients with advanced or relapsed gastric cancer and normal individuals. Age: The significant difference (P<0.01) was present between the gastric cancer patients under 59 years and normal individuals. Conclusion: The increased level of CD44 in the PB of patients with gastric cancer indicated the possible existence of relapse, advance or metastasis of tumors. When the tumor was poorly differentiated and bigger in tumor mass, the level of CD44% would be higher. Examining the level of CD44 by flow cytometry in the periphery blood of patients with gastric cancer was useful for the prognosis. Method: Both the level of CD44 and the immunocyte phenotype of the lymphocytes of 110 patients with gastric cancer and 100 healthy Subjects were examined by flow cytometry, and the results were analyzed pathologically and consistent ly. Results: The mean of the CD44% in PB of the held subjects 46.14 (13.4 and there were no statistic differences for their age and sex. Site of tumor growth : The significant difference (P<0.01) was present between the patients with the cardiac part (C) or body of gastric (M+C) cancer and normal individuals. The significant difference (P<0.05) was present between patients with the 3 Place of gastric cancer and normal individuals. Type of tumor mass: The significant difference (P<0.05) was present between patients with mixed type gastric cancer and normal individuals. Size of tumor mass: The si The degree of tumor differentiation: The significant difference (P<0.01) was present. Between the patients with low differentiation gastric cancer and normal individuals. The significant difference (P<0.01) was present between patients with metastatic stage: The significant difference (P<0.0l) was present lymph node gastric cancer and normal individuals. Clinical between the Patients with advanced or relapsed gastric cancer and normal individuals. Age: The significant difference (P<0.01) was present between the gastric cancer patients under 59 years and normal individuals. If the tumor is poorly differentiated and bigger in tumor mass, the level of CD44% would be higher. Examining theLevel of CD44 by flow cytometry in the peripheral blood of patients with gastric cancer was useful for the prognosis.