Background. Angiogenesis and hemostatic activation are important factors in tumor progression and metastasis. Because surgical intervention induces tissue hypoxia and hemostatic activation, we analyzed the effect of gastric surgery on the plasma concentrations of vascular endothelial growth factor (VEGF), soluble P-selectin (sP-selectin), and von Willebrand factor (vWf). Methods. Plasma VEGF, sP-selectin, and vWf concentrations were measured in 14 patients with gastric cancer before operation and on postoperative day 1 (POD 1). Correlations between disease stage and the effect of surgical intervention were analyzed. Results. The plasma concentrations of these three factors did not correlate with the disease stage. Plasma levels of sPselectin did not change after operation (before surgery, 87.6 ؎ 34.1 ng /ml; on POD 1, 101.1 ؎ 48.1 ng/ml; P ؍ 0.123). Plasma VEGF and vWf concentrations were significantly elevated on POD 1 (VEGF, 33.3 ؎ 20.5 pg /ml before surgery and 61.9 ؎ 35.6 pg /ml on POD 1; P ؍ 0.0013; vWf, 164 ؎ 31.1% before surgery and 211.1 ؎ 66.1% on POD 1; P ؍ 0.027). Conclusion. Because VEGF and vWf are involved in angiogenesis, tumor-platelet adhesion, and tumor-endothelial cell adhesion, surgical intervention could influence tumor growth and metastasis.