Objective: To investigate the expression of cyclooxygenase (Cox)-2 in carcinoma of the gastric cardia, and to evaluate the relationship between Cox-2 expression and angiogenesis. Methods: Forty-six resected tumor specimens from patients with carcinoma of the gastric cardia were collected, and 21 corresponding paracancerous normal tissues were randomly selected as controls. Immunohistochemical staining was used for detecting the expression of Cox-2. Monoclonal antiboty against CD34 was used for labeling vascular endothelial cells, and microvascular density (MVD) was determined by counting CD34-positive vascular endothelial cells. The correlations of Cox-2 expression and MVD with clinicopathological parameters of the patients were analyzed. Results: The positive expression rate of Cox-2 and MVD value in the cancerous tissue were 80.4% and 31.95 ± 3.87, respectively, which were significantly higher than those in the pericancerous normal tissues (14.3%, 16.28 ± 1.55; P <0.01). The positive expression level of Cox-2 and MVD value were associated with clinical TNM staging and lymph node metastasis. The Spearman rank correlation test showed that tumor MVD were closely associated with Cox-2 expression. Conclusion: Abnormal expression of Cox-2 and angiogenesis play important roles in tumor invasion and lymph node metastasis of carcinoma of the gastric cardia.