BACKGROUND: To overcome the limitation of angiography, intravascular ultrasound(IVUS) is widely used to guide coronary stent implantation. We compared the quantitative measurements of IVUS and quantitaitve coronary angiographic(QVA) analysis after stent implantation. METHODS: Thirty nine patients with 39 coronary lesions underwent coronary stent implantation. The implanted stents were CrossFlex stent in 17, NIR stent in 13, Palmaz-Schatz stent in 6, Multilink stent in 2 patients, and Divysio stent in 1 patient. Post-stent IVUS procedure with automatic pullback device was performed successfully in all patients after angiographic optimization. IVUS and QCA measurements included the minimum lumen diameter at proximal and distal reference artery, and stented site after intracoronary administration of 0.2mg nitroglycerin. RESULTS: IVUS and QCA measurement of minimal luminal diameter(MLD) at proximal and distal reference artery, and stented site correlated reliably each other(r=0.62, p<0.01 ; r=0.77, p<0.01 ; r=0.73, p<0.01 respectively). Event if insignificant statistical difference, there was a tendency of larger MLD at proximal and distal reference artery by IVUS measurement than by QCA measurement(3.2+/-0.5mm vs. 3.1+/-0.4mm, p=0.2 : 3.1+/-0.6mm vs. 3.0+/-0.7mm, p=0.2, respectively). The MLD at stented site was significantly larger by QCA measurement than by IVUS measurement(3.2+/-0.6mm vs. 2.9+/-0.5mm, p<0.05). CONCLUSIONS: We concluded 1) the correlation between IVUS and QCA measurements of reference vessel and stented site was reliable. 2) There was a tendency of larger luminal diameter at reference vessel by IVUS than by QCA. 3) The minimal luminal diameter was measured significantly larger at stented site by QCA than by IVUS.