Abstract: To study the significance of tumor angiogenesis in the invasion and metastasis of gastric cancer, microvessel density(MVD) was determined on the same 68 gastric carcinoma specimens with immunohistochemical staining method using monoclonal antibody QB-END/10 against CD34 antigen. The results showed that in all gastric carcinoma tissues, the mean MVD was 18. 2± 10. 9, which increased proportionally with the depth of invasion and TNM stages. The petients with lymph node metastasis had a mean MVD of 20. 85± 10. 19, much higher than those without lymph node metastases who had a mean MVD of 14. 32± 10. 67 (P0.01). The patients with the invasion to blood vessels and nerves by gastric carcinoma cells had a much higher MVD than that of those without such invasions (P< O. 01). Both monofactorial and multifactorial analyses showed that patients with high MVD (≥18) had a much poorer prognoses than those with low MVD(<18) (P<0. 05), indicating that MVD was a solitary factor influencing prognosis. In conclusion, tumor angiogenesis was an essential step toward cancer invasion and metastasis, and MVD was an useful parameter to the assessment of the invasive and metastatic potentials of gastric carcinoma and also to the making of prognosis.