Background: Several studies have indicated that the clinical outcomes of sirolimus-eluting stents (SES) are significantly associated with longitudinal positioning of the stent relative to the underlying plaque distribution. Methods and Results: Optimal SES landing was determined using unique stepwise intravascular ultrasound (IVUS) criteria, mainly targeting the sites with plaque burden <50% (plaque area/external elastic membrane area ×100). To verify the criteria, (1) achievability and (2) actual impact on clinical and angiographic outcomes were assessed. A total of 162 consecutive patients with 180 lesions were enrolled and treated according to the IVUS criteria. Plaque burden at the proximal and distal margins was 41.4±13.6% (n=144) and 34.9±15.6% (n=170), respectively (within 3 mm of stent ends). The target was achieved in 72.3% of the proximal and 84.1% of the distal margin for the criteria. A strikingly low angiographic margin re-stenosis rate (2.7% of proximal and 1.4% of distal margin) and low target lesion revascularization rate (2.2%) were achieved. Receiver operator characteristic curve indicated that plaque burden was the strongest predictor of margin re-stenosis and its threshold (51.6%) was almost identical to that of the criteria. Conclusions: The proposed stepwise IVUS criteria mainly targeting plaque burden <50% are feasible and useful in the real-world practice of SES implantation.  (Circ J 2010; 74: 1609 - 1616)