Background: This study was conducted to evaluate the neointimal hyperplasia and the inflammatory responses depending on the administration duration of cilostazol on overlapping drug-eluting stents in the porcine model. Methods and Results竊�48 overlapping biolimus-eluting stents (BESs) were deployed in the left anterior descending coronary and left circumflex artery of 12 non-injured pigs. Pigs were divided as follows: Group I (n=4) received aspirin 100mg and clopidogrel 75mg daily for 8 weeks, Group II (n=4) received aspirin 100mg and clopidogrel 75mg daily for 8 weeks and cilostazol 200mg daily for 4 weeks, Group III (n=4) received aspirin 100mg, clopidogrel 75mg and cilostazol 200mg daily for 8 weeks. Follow-up coronary angiograms and histologic analyses were performed at 8 weeks after stenting. In quantitative coronary angiographic analyses, the minimal luminal diameter of group III was more larger than that of the other group (1.92짹0.29mm vs. 1.72짹0.29mm vs. 2.64짹0.31mm, respectively, p=0.001). Histological analyses showed that the lumen area of group III was also more larger than that of the other group (2.71짹0.74mm2 vs. 2.55짹0.22mm2 vs. 3.56짹0.24mm2, respectively, p=0.043) and group III tended to have a smaller percent area stenosis compared to other groups (47.95짹11.97% vs. 49.95짹5.46% vs. 36.89짹7.99%, p=0.155). However, the neointimal area were no different among 3 groups (2.45짹0.51mm2 vs. 2.55짹0.36mm2 vs. 2.11짹0.61mm2, respectively, p=0.433). The inflammatory score were also no different among 3 groups (1.45짹0.29 vs. 1.28짹0.25 vs. 1.46짹0.07 respectively, p=0.540). Conclusion竊�Although our study fails to demonstrate a beneficial effect of cilostazol in histologic analyses, it shows that long-term administration of cilostazol seem to be more effective to reduce angiographic restenosis in the overlapping BESs.