The effects of sardine diet on blood lipids and hemostasis were investigated. Five healthy male subjects took a daily 300g of canned sardine for 1 week. After taking sardine eicosapentaenoic acid (EPA) contents increased but arachidonic acid (AA) contents did not change in plasma. Therefore, plasma EPA/AA ratio was elevated after taking sardine (before; 0.35±0.22, after; 1.18±0.84). Platelet aggregation induced by ADP (final concentration; 0.6μM and 1.8μM), collagen (1.4μg/ml), adrenaline (1.3mg/ml), A23187 (2.5μM), PAF (1.0μg/ml) or ristocetin (1.2mg/ml), as well as platelet adhesiveness, was not inhibited by taking sardine. The venous occlusion test was done before and after taking sardine. In the pre-occlusion plasma, sardine diet had no effect on the euglobulin lysis time (ELT), von Willebrand Factor (vWF): Ag, plasminogen, plasminogen activator and protease inhibitor (α2PI, α1AT, α2M, C1-INA). In the post-occlusion plasma, a shortening of ELT and a increased concentration of vWF: Ag and plasminogen activator were significant after taking sardine. These results demonstrate that the release of vascular plasminogen activator and vWF: Ag from the endothelium was accelerated by taking sardine. This effect of sardine diet on the plasminogen activator release may prevent thrombosis.