The purpose of this work is to investigate the correlation between regional oxygen saturation (rSO(2)) changes and stump pressure (SP) during cross-clamping of the internal carotid artery in carotid endarterectomy (CEA) and verify the perspectives of rSO(2) to become a criterion for shunting. Sixty consecutive CEAs under general anesthesia were studied prospectively. Selective shunting was based on SP ≤40 mmHg exclusively. Regression analysis with high order terms and receiver operating characteristic analysis were performed to investigate the association between ΔrSO(2)(%) and SP and to determine an optimal ΔrSO(2)(%) threshold for shunt insertion. A quadratic association between ΔrSO(2)(%) and SP was documented regarding the baseline to one and five minutes after cross-clamping intervals. A cut-off of 21 and 10.1% reduction from the baseline recording was identified as optimal for the distinction between patients needed or not a shunt regarding the first and fifth minute after cross-clamping, respectively. In conclusion, cerebral oximety reflects sufficiently cerebral oxygenation during CEA compared with SP, providing a useful mean for cerebral monitoring.