Background: In the era of drug-eluting stent (DES), the importance of minimal lumen diameter (MLD) has been on the decrease. However, the largest available size of DES is 3.5���. When you meet larger reference vessel diameter (RVD) than 3.5mm, you might think over which type of stent should be deployed. Purposes: The aim of this study is to clarify the incidence of major adverse cardiac event (MACE) after 4.0��� sized bare metal stent (BMS) implantation compared with 3.5��� DES, and the need of a larger sized DES. Methods: This retrospective study included 164 patients (180 lesions) from Jun. 2002 to Aug. 2004, who underwent coronary stent (RVD within 3.5~4.0���, BMS 4.0���, DES 3.5���). All patients were divided into two groups: group 1 BMS, group 2 DES. The clinical outcomes and follow-up coronary angiographic result were analyzed. Results: 12months clinical follow-up was available in 93.9%, 6 months angiographic follow up in 51.1%. Other data are in the following table. Conclusions: Although ISR rate was more frequent in BMD, MACE was not different between two groups. Until now, we recommend BMS in large coronary artery, which could not be deployed with 3.5��� sized DES. Large scaled, randomized prospective study would be required.