Background: Quantitative coronary angiography (QCA) can predict late clinical restenosis in patients undergoing drug-eluting and bare metal stent placement by measuring percent diameter stenosis and late lumen loss on follow-up angiography. Our study objective: was 2D-QCA stenosis area percentage in predicting the functional significance of intermediate stenosis considering IFR as the gold standard for accurate decision maker regarding revascularization. Methods: This study was carried out on 155 patients diagnosed as symptomatic IHD referring for doing ICA and found to have intermediate coronary lesions. All patients underwent both (QCA) and Instantaneous Free Wave Ratio (IFR) for evaluation of each intermediate lesion. Each intermediate lesion was then allocated to one of 3 groups based on the affected vessel LAD group, LCX group and RCA group then dividing borderline lesion stenosis based on QCA AS 50-60 % and 61-70 % comparing with IFR in three vessels. Results: There was statistically significant positive correlation between QCA area stenosis 50 to 60 %, 61-70 % in mid LAD lesions (P value= 0.0001, P value= 0.0001) while there was statistically significant negative correlation between QCA area stenosis 50 to 60 % in mid and proximal RCA lesions (P value= 0.0002, P value= 0.0001). Conclusion: LCX lesions were the ones where sensitivity and specificity showed the highest in prediction of IFR outcome in area stenosis 50-60 %. While in area stenosis 61-70 % LAD lesions have the highest prediction of IFR outcome.