Objective: To determine the expressions of CXCR4 and CD133 in the primary lesions of gastric cancer, and their influences on lymphatic metastasis. Methods: The primary tumor tissues and their adjacent normal mucosal tissues were taken from 50 gastric cancer patients. In these tissues, the location of CXCR4 and CD133 expression was detected by immunohistochemical staining, the gene and protein expression levels of CXCR4 and CD133 were determined by semi-quantitative RT-PCR and Western blot, respectively. and the correlations between CXCR4 and CD133 and their relations with lymphatic vessel invasion and lymph node metastasis were analyzed. Results: The CXCR4 and CD133 molecules were both expressed on the membranes of tumor cells and very small amount of CXCR4 was found in the nucleus. The positive expression rates as well as the gene and protein expression levels of CXCR4 and CD133 in gastric cancer tissues were all significantly higher than in those of the normal mucosal tissues (all P<0.05). The relative gray scale values of both CXCR4 and CD133 mRNA were significantly higher in the tumor tissues of the group with lymph node metastases than in those without lymph node involvement (P=0.011 and P=0.038). The relative gray scale value of the CXCR4 protein in the tumor tissues of the group with N1 lymph node involvement was significantly higher than in those without lymph node metastasis (P=0.023), but was lower than in those with N2+N3 lymph nodes involvement (P=0.008). The relative gray scale value of the CD133 protein in the tumor tissues of the group with N1 or N2+N3 lymph node involvement was significantly higher than in those without lymph node involvement (P=0.04 and P=0.01), but there was no significant difference between the N1 and N2+N3 groups. The relative gray scale values of CXCR4 and CD133 protein in the tumor tissues of the group with lymphatic vessel invasion were significantly higher than in those without lymphatic vessel invasion (P<0.05). Of the patients with lymph nodes metastases, the relative gray scale values of both CXCR4 and CD133 protein were positively correlated with the number of lymph nodes involved (r=0.480, r=0.426) and the ratio of metastatic lymph nodes (r=0.502, r=0.489). Conclusion: CXCR4 and CD133 present high expression and are positively correlated in the primary lesion of stomach cancer, and the expression of both of these proteins is associated with the metastatic lymph node ratio and number. It is speculated that under the mediation of CXCR4, lymphatic vessel invasion and metastasis of CD133 postitive tumor cells is more easily induced.