Cine magnetic resonance imaging (MRI) was used to assess aortic regurgitation (AR) in 13 patients with valvular disease and 3 normal subjects, and the results were compared to color Doppler flow mapping findings. AR produced a signal void in the left ventricle during the diastolic phase in all patients by MRI. There were no false positive or negative results compared with echocardiographic findings. Visual grading of cine MRI gave results similar to color flow Doppler echocardiography (88%). The distance and the area of aortic regurgitation using MRI correlated well with color Doppler flow mapping (r = 0.82 and 0.88). However, measurements of distance and area by color flow Doppler tended to be larger than those by cine MRI. With current techniques echocardiography may overestimate the severity of AR as compared with cine MRI. In addition, MRI gives clinically useful information in patients in whom transthoracic Doppler echocardiography is not adequate.