Backgrounds: Even though intravascular ultrasound (IVUS) provides 3-D anatomic image of coronary artery, it might overestimate real functional significance of the coronary lesion during percutaneous coronary intervention (PCI). FFR-guided PCI strategy was reported to be safe and effective. The aim of this study is to evaluate the safety and efficacy of FFR-guided PCI strategy compared to IVUS guided PCI in daily practice. Methods: Four hundred forty four patients (350 patients of IVUS guided, 94 of FFR guided) were consecutively included from Nov. 2006 to June 2007. All patients were divided to IVUS guided and FFR guided group. If both procedures were simultaneously used, that patients were included to FFR guided group. Major adverse cardiac events (MACE: cardiac death, myocardial infarction and target vessel revascularization (TVR)) were assessed at 12 months after the procedure. Results: Mean age was higher in FFR guided group than IVUS guided group (63.5짹8 vs. 61.2짹10, p=0.021). IVUS guided group had more underwent revascularization therapy, also had more implanted stent number than FFR guided group (95.4% vs. 78.7%, p<0.001, 1.67짹1.1 vs. 1.3짹1.1, p=0.003). One year clinical follow-up was available in 98.6%. No difference was found in 12-month MACE rates between 2 groups (Table). There was no death or MI related to the lesions in FFR guided group. Conclusions: FFR-guided PCI strategy resulted in excellent long-term outcomes, similar as IVUS guided PCI. However, FFR-guided strategy reduced the need for PCI.