To assess the association between cerebral arterial stiffness measured using the carotid–cerebral pulse wave velocity (ccPWV) and the functional outcome after acute ischemic stroke (AIS). We prospectively studied 336 consecutive patients (mean age, 60.58 ± 9.89 years; 73.81% male) with first-ever AIS who underwent examination by multimodal brain magnetic resonance, ccPWV, echocardiography, and carotid ultrasonography during the admission period. Ischemic stroke subtypes were classified using the Trial of Org 10172 in Acute Stroke Treatment classification system. A poor functional outcome was defined as a modified Rankin Scale score >2 at 3 months after stroke onset. We observed that 110 (32.74%) patients had a poor functional outcome. Multivariate logistic regression analysis revealed that ccPWV ≥ 6.66 m/s, calculated from the receiver operating characteristic (ROC) curve, was an independent predictor of a poor functional outcome [adjusted odds ratio, 6.27; 95% confidence interval (CI), 2.07–18.99]. ROC curve analysis showed that the area under the curve of ccPWV for predicting the 3-month functional outcome after AIS was 85.27% (95% CI, 80.95–89.58; P < 0.001). The optimal ccPWV cutoff point was 6.66 m/s, with a sensitivity of 82.73% and specificity of 77.88%. Furthermore, the addition of ccPWV to the predictive model significantly improved the discrimination ability for a poor functional outcome. Cerebral arterial stiffness, measured using the ccPWV on admission, has value as an independent prognostic factor for predicting the long-term functional outcome in patients with AIS. © 2019, The Japanese Society of Hypertension.