Twenty-five consecutive elderly patients with suspected aortic stenosis underwent continuous-wave Doppler echocardiography followed by cardiac catheterization. Doppler-derived calculations of peak and mean aortic valve gradients were compared with catheterization-derived values of peak-to-peak, peak and mean gradients. The best correlation was found between Doppler- and catheterization-derived mean gradients (r = 0.89). A Doppler-derived measure of the timing of peak aortic flow velocity (modified time-to-peak velocity/modified left ventricular ejection time) successfully separated those with gradients above or below 50 mm Hg and also helped to avoid over- or underestimation of aortic valve gradients by Doppler.