Background: In-stent restenosis (ISR) progresses involves numerous cellular and molecular constituents. Platelets and macrophages play a central role via vascular smooth muscle cell migration and proliferation in the intima to produce neointimal hyperplasia, which is pathognomic of ISR. Previous data showed that monocytes play a important role in in-stent restenosis (ISR) after stent implantation. IVUS guided DES implantation has improved clinical results in patients undergoing PCI. Stent under-expansion and malposition have been identified as the key mechanisms of DES failure. This study assessed the relationship between preinterventional white blood cell count, platelete count and ISR after successful stent implantation. Methods: Patients having IVUS guided intervention with DES implantation were consecutively registered. We performed IVUS guided coronary DES implantation in 120 patients (123 de novo lesions). Intravascular ultrasound-guided high-pressure balloon dilatation was done for optimal drug-eluting stent implantation. Peripheral blood sample was obtained in all patients before and after PCI. ISR was evaluated at 10 months after stenting by follow-up coronary angiograms, and it was defined as >50% diameter stenosis of the target lesion. Results: Among 120 patients, 73 patients received angiographic follow-up at 10 months after stenting. The incidence of ISR was 17.8%(13 of 73). The preinterventional white blood cell count was significantly higher in the ISR group than that in the group without ISR (11.0 짹 6.5���10³ vs. 8.4 짹 3.6���10³ /mm³, p = 0.035) and the preinterventional platelet count has no significant difference between in the ISR group and in the without ISR group (270.0 짹 43.5���10³ vs. 244.7 짹 67.8���10³ /mm³, p = 0.083). Conclusion: Our results suggest that circulating white blood cell may play a role in the progress of in-stent neointimal hyperplasia after successful stent implantation.