Objective: The aim of this study was to evaluate the performance of common carotid artery diameter, flow velocity and flow velocity/artery diameter ratio as predictors of major adverse cardiovascular events (MACEs) in a sample of hypertensive patients. Methods: A cohort of 403 hypertensive patients was followed up for a median of 1260 (714) days, and 27 suffered MACEs. At baseline, participants were evaluated by clinical, laboratory, echocardiographic and carotid ultrasound analysis. Results: Patients with peak-systolic flow velocity (sFV) less than the median value and systolic artery diameter (sAD) greater than the median value presented the worst clinical outcome compared to those with isolated sFV less than the median value or sAD greater than the median value, suggesting an additive effect of these two variables. Further, Kaplan-Meier analysis demonstrated worse outcome for individuals with sFV/sAD ratio less than 85.7/s (optimal cut-off point obtained by receiver-operating characteristic analysis) compared to those with higher sFV/sAD values (log-rank test: P<0.0001). In stepwise multivariable Cox-regression analyses, sFV/sAD was significantly associated with MACEs (P<0.001), whereas carotid intima-media thickness and clinically defined high cardiovascular risk did not. Furthermore, area under the receiver-operating characteristic curve for sFV/sAD was higher than that for Framingham risk score (0.77 versus 0.64; P=0.045), whereas adding sFV/sAD to the Framingham risk factors resulted in increased net reclassification improvement (P=0.041) and integrated discrimination improvement (P<0.001). Conclusions: Lower carotid sFV/sAD was associated with MACEs in hypertensive patients independent of cardiovascular prediction models and carotid intima-media thickness. These findings suggest that this index may be a promising approach to identify hypertensive subjects at increased risk for future cardiovascular events.