Background The SES SMART study demonstrated the superiority sirolimus eluting stents in small coronary arteries. However, SES SMART study tended to have short lesions (mean 11.6mm). So, we evaluated the efficacy of drug-eluting stent(DES) for restenosis reduction in unselected small coronary lesions (less than 2.75mm in diameter). Methods From July 2003 to March 2005, commercially available DES, Cypher or Taxus, were implanted into 100 consecutive patients with 106 lesions. All patients received aspirin indefinitely and clopidogrel for 6 months. The primary endpoint was angiographic insegment restenosis at 6 month and the secondary end point was major adverse cardiac events (nonfatal myocardial infarction, death, target lesion revascularization) at 9 months. Results Mean age was 63 years old, with 52% male, 23% diabetics, 32% current smokers, 55% hypertnesion. Total 118 DESs (mean 1.1/lesion), were implanted into 106 lesions. Mean reference vessel diameter was 2.44 mm and lesion length was 21.77mm. The mean pre- and post- minimal lumen diameter was 0.62mm , 2.28mm, Mean stent size and length was 2.67mm, 28.11mm. One procedure-related death occurred . There were no other in-hospital events including acute myocardial infarction, target lesion revascularization, or stent thrombosis. Six-month angiographic follow-up was performed in 79% of the eligible patients. In-segment restenosis rate was 19.8% and in-stent restenosis rate was 16.0%. Late loss was 0.42mm. There were no differences of in-segment restenosis between long(���25mm) and short lesions(<25mm) (21.1% vs 18.6%, p=0.79), and between Cypher and Taxus (19.2% vs 20.7%, p=1.0) Conclusion The DES implantation in small coronary arteries reduced the rate of restenosis. But it needs more large scale studies to clarify the efficacy of the DES in small coronary arteries.