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 for intermediate coronary disease. Methods: One hundred eighty four patients (93 patients of FFR guided, 91 of IVUS), who had intermediate coronary disease (percent diameter stenosis between 70% and 40%), were consecutively included from Nov. 2006 to June 2008. Cut-off value of FFR in FFR guide PCI was 0.80 and cut-off value of minimal lumen area in IVUS guided PCI was 4.0mm2. All patients were divided to FFR guided and IVUS guided group. Major adverse outcomes (death, nonfatal myocardial infarction and target vessel revascularization (TVR)) were assessed at 12 months after the procedure. Results: Mean pre-interventional diameter stenosis was similar in both groups (55짹7% in FFR vs. 53짹8% in IVUS, p>0.05). IVUS guided group had more underwent revascularization therapy (90% vs. 43%, p<0.001), also had more implanted stent number than FFR guided group (1.3짹0.8 vs. 0.9짹1.2, p=0.03). One year clinical follow-up was available in 100%. No difference was found in 12-month MACE rates between 2 groups (Table). By multivariate analysis, performing intervention was affected by guided device (FFR vs IVUS, p<0.001, OR 0.06, CI 0.02-0.14), history of diabetes (p<0.032, OR 2.84, 1.10-7.35). Conclusions: FFR-guided PCI strategy for intermediate coronary disease resulted in good long-term outcomes as IVUS guided PCI. However, FFR-guided strategy reduced the need for PCI.