Objective: Autologous saphenous veins are widely used for coronary artery bypass surgery (CABG) despite a higher incidence of graft closure. Early initiation of antiplatelet drugs reduces the incidence of graft occlusions. In this study, we assessed the aspirin resistance by PFA-100® (Platelet Function Analyzer) system in the patients with saphenous vein graft (SVG) occlusion. Material and Methods: Fourty-four patients who underwent cardiac catheterization were evaluated. Patients were divided into two groups according to SVG patency. Patients with occluded SVG were compared with patients with patent SVG in terms of clinical, angiographical and laboratory parameters. Results: Thirteen of 44 (29.5%) patients were aspirin non-responder. The number of non-responders in patients with and without occlusion in SVG were similar (35% vs 24%, p= 0.4). Basal characteristics and mean aperture closure time/ADP (CT/ADP), aperture closure time/epinephrine (CT/EPI) values were similar in patients with occluded and patent SVGs. Hyperlipidemia was only significantly increased the risk of SVG occlusion in multivariate analysis. There was no significant difference between aspirin responders and nonresponders in terms of clinical parameters, major cardiovascular risk factors, occlusion in SVGs in any time period. However, mean platelet volume, CT/EPI and CT/ADP values were higher in the non-responder group. CT/EPI was negatively correlated with mean platelet volume and hematocrit levels. Conclusion: Aspirin resistance does not seem to play an important role in SVG occlusion. © 2010 by Türkiye Klinikleri.