Objectives:Platelets play significant role in the pathogenesis of in-stent restenosis (ISR). Platelet distribution width to platelet count ratio (PDW/platelet) is a new marker. There are no data available regarding the predictive role of PDW/platelet ratio for ISR in patients with coronary artery disease. The present study aimed to search the predictive value of preprocedural PDW/platelet ratio on in-stent restenosis in patients with stable or unstable angina pectoris undergoing coronary bare-metal stent implantation.Materials and Methods:We retrospectively analyzed clinical, biochemical, and angiographic data from 763 consecutive patients [mean age 60.3±10.2 years, 546 (71%) male]; all patients had undergone elective bare-metal stent implantation and further control coronary angiography owing to angina pectoris or ischemia.Results:The mean period between stent implantation and control coronary angiography procedures was 15.3±8.7 months. The preprocedural PDW/platelet ratios were significantly higher in patients that had ISR (odds ratio, 3.43; 95% confidence interval, 2.02-5.83; p<0.001). Smoking, uric acid, C-reactive protein levels and PDW/platelet levels identified as independent predictors of ISR.Conclusion:Our results demonstrate that higher PDW/platelet ratio is an independent and powerful predictor of ISR in patients with stable or unstable angina pectoris who underwent successful bare-metal stent implantation.