We studied 16 patients with chronic aortic insufficiency to compare a method for measuring regurgitant volume with color Doppler flow mapping to stroke count ratio determined by radionuclide ventriculography and to ventricular volumes assessed by two-dimensional echocardiography. A real-time color flow map of the left ventricular was obtained from an apical two- and five-chamber view and the maximal mosaic pattern of diastolic turbulent flow was planimetered as a reflection of the maximal regurgitant volume using biplane Simpson's rule. The maximal Doppler regurgitant volume evaluated by color Doppler flow mapping correlated with the stroke count ratio measured by scintigraphy (r = 0.86, SEE = 11 cc). There were significant relationships between maximal regurgitant volume measured by color Doppler and echocardiographic left ventricular end-diastolic volume (r = 0.88), left ventricular end-systolic volume (r = 0.77), and left ventricular mass (r = 0.71). Patients with larger regurgitant volumes tended to have a larger left ventricular end-diastolic volume-to-mass ratio (r = 0.56). Thus maximal aortic regurgitant volume can be estimated noninvasively with color Doppler flow mapping. The measurement appears to relate to left ventricular morphologic changes occurring in this condition and it may prove to be useful in assessing patients with chronic aortic insufficiency and in determining their long-term management.