Backgroud Even in drug eluting stent (DES) era, in-stent restenosis (ISR) still remained as a major problem. We investigated the effectiveness of DES implantation compared with cutting balloon angioplasty (CBA) for ISR of DES. Methods 55 ISR lesions (46 patients) were analysed retrospectively. DES implantation (N=34) or CBA (N=21) was performed in ISR lesions. 6 month follow up angiography were obtained. The clinical information was reviewed by medical records. Results 19 ISR lesions were developed in Sirolimus-eluting stents and 36 ISR lesions in Paclitaxel-eluting stents. 31(56.5%) ISR lesions were at left anterior descending artery. ISR pattern was like as followings. 40 was focal (72.7%), 12 diffuse (20.0%), 1 diffuse proliferative (1.8%), and 3 occlusive lesions (5.5%). The clinical characteristics and quantitative angiographic analysis data before percutaneous coronary intervention (PCI) were not different between DES group and CBA group. As shown in Table, DES group gained larger minimal luminal diameter and more acute gain than CBA group immediately after PCI. 6 month follow up angiography was performed in 64% of ISR lesions. DES group showed significantly lower late loss, incidence of ISR (10.0 vs 42.8%,p<0.05) and TLR (0 vs 28.5%,p<0.05) after treating ISR of DES than CBA group. Conclusions DES implantation significantly reduced second ISR and TLR compared to CBA for ISR following DES.