3D echocardiography provides a complete evaluation of the aortic valve and adjacent structures and it improves the assessment of this cardiac region. Three-dimensional color-Doppler echocardiography (3DCDE) evaluation might improve the measurements of the functional regurgitant orifice in patients with Chronic Aortic Regurgitation (CAR).Our aim was to compare the accuracy of current echo-Doppler methods and 3DCDE for the assessment of CAR severity. The reference method used in this work was the CAR severity determined by means of cardiac magnetic resonance (CMR)Thirty-two consecutive patients with an established diagnosis of CAR recruited in our institution comprised our study group. CAR severity was determined by conventional Echo-Doppler methods and by 3DCDE and their results were compared with those obtained by means of CMR.Mean age was 63.0±13.5years. Twenty-two patients (68.8%) were men. Compared with the traditional echo-Doppler methods, 3DCDE evaluation had the best linear association with CMR results (3D vena contracta cross sectional area method: r=0.88; r square=0.77; p<0.001. 3D vena contracta cross sectional area/left ventricular outflow tract cross sectional area method: r=0.87; r square=0.75; p<0.001). The ROC analysis showed an excellent area under curve for detection of severe CAR (3D vena contracta cross sectional area method=0.97; 3D vena contracta cross sectional area/left ventricular outflow tract cross sectional area method=0.98). Inter- and intra-observer variability for the 3DCDE evaluation was good (ICC=0.89 and ICC=0.91 for inter and intra observer variability respectively).3DCDE is an accurate and highly reproducible diagnostic tool for estimating CAR severity. Compared with the traditional echo-Doppler methods, 3DCDE has the best agreement with the CMR determined CAR severity. Thus, 3DCDE is a diagnostic method that may improve the therapeutic management of patients with CAR.