Dietary intake of omega-3 polyunsaturated fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been reported to have beneficial cardiovascular effects. However, little is known about the effect of EPA and DHA on human vascular tone. Therefore, the aim of this study is to evaluate the effect of EPA and DHA on vascular tone of the human saphenous vein (SV) obtained from patients undergoing coronary bypass operation under normal and inflammatory conditions. Moreover, we aimed to investigate the effect of EPA and DHA on the release of inflammatory mediators from SV. Pretreatment of SV with EPA and DHA (100μM, 18h) decreased the contractile response of SV to norepinephrine (NE) under normal and inflammatory conditions. Moreover, EPA and DHA pretreatment diminished increased Monocyte Chemoattractant Protein-1 (MCP-1) and Tumor Necrosis Factor-alpha (TNF-α) release from SV under inflammatory conditions. In conclusion, our results suggest that EPA and DHA pretreatment may be beneficial to counteract graft vasospasm and vascular inflammation in SV which are important factors in graft failure development. Therefore, dietary intake of EPA and DHA may have potential clinical applications in improving coronary bypass graft patency.