Methods and Results:The OFR and FFR were measured in 103 coronary arteries immediately after successful PCI with a stent. An increase in the OFR and FFR values within the stent was defined as in-stent ∆OFR and ∆FFR, respectively. The values of FFR and OFR were 0.89±0.06 and 0.90±0.06, respectively. OFR was highly correlated with FFR (r=0.84, P<0.001). OFR showed a good agreement with FFR, presenting small values of mean difference and root-mean-squared deviation (FFR–OFR: −0.01±0.04). In-stent ∆OFR showed a moderate correlation (r=0.69, P<0.001) and good agreement (in-stent ∆FFR – in-stent ∆OFR: 0.00±0.02) with in-stent ∆FFR.