To test whether continuous wave Doppler (CWD) echocardiography would be useful for diagnostic evaluation of valvular heart diseases, CWD echograms of 159 abnormal valves with stenosis or insufficiency (35 mitral stenosis, 30 mitral insufficiency, 25 aortic stenosis, 30 mitral insufficiency, 3 tricuspid stenosis, 30 tricuspid insufficiency, 6 pulmonary stenosis, 8 pulmonary insufficiency) were studied for 1) the sensitivity in the diagnosis of various valvular diseases, 2) the quantitative assessment of pressure gradient across the valve of mitral stenosis or aortic stenosis, and 3) the measurement of right ventricular pressure in patients with tricuspid regurgitation. A Doppler transducer was applied to minimize the angle formed by the beam and the jet, and final adjustment in beam direction was determined by the Doppler audio signal. The results were as follows. 1) CWD echo was a very sensitive technique in the diagnosis of all kinds of valvular diseases. 2) Doppler-pressure studies demonstrated that CWD echo provided a quantitative assessment of severity of mitral or aortic stenosis. Pressure gradients from CWD echo was well correlated with those from catheterization (r=0.92 in mitral stenosis and r=0.83 in aortic stenosis). 3) The right ventricular pressure measured by adding 10 mmHg to the pressure gradient from CWD echo in patients with tricuspid regurgitaion was almost the same with those from catheterization (r=0.99). It is concluded that CWD echo is a useful, noninvasive method in the qualitative and quantitative assessment of valvular heart diseases.