This study investigated whether the jet diameter measured by a multigated pulsed Doppler system could be used to assess the severity of valve disease in children with pulmonary (n = 11) or aortic (n = 4) valve stenosis. The results obtained were compared with those obtained at cineangiography and at operation. Multigated pulsed Doppler examination of a stenosed valve showed a region of relatively high velocities in the velocity profile (jet flow). There was good agreement between the diameter of the disturbed region on the Doppler echocardiogram and the diameter of the jet on the lateral angiocardiogram. In severe valve stenosis the agreement between the valve diameters measured by multigated pulsed Doppler and at operation was also good. In less severe valve stenosis Doppler measurements systematically underestimated the valve diameter at operation. It is likely that the functional opening of a semilunar valve is a more relevant estimate of the degree of stenosis than the anatomical measurement of the orifice. The findings of this study indicate that multigated pulsed Doppler systems are useful in the noninvasive diagnosis of stenotic valve disease.