Two-dimensional Doppler echocardiographic velocity profiles of four cardiac valves in a group of 85 infants and children with left to right shunt lesions(VSD, ASD and PDA) are presented. Velocities were obtained before operation and 10 days afterward. The results were as follows ; 1) VSD(type 2) Peak velocities of mitral valve were significantly decreased when compared preop. with postop. echocardiogram(n=37, preop 132+/-24, postop 98+/-16 cm/sec, p<0.0005). Peak velocities of tricuspid valve were also significantly decreased(n=30, perop 60+/-21, postop 50+/-17cm/sec, p<0.01). Peak velocities of aortic valve were decreased(n=18, perop 120+/-20, postop 108+/-26cm/sec, 0.010.05). Peak velocities of pulmonic valve were significantly decreased(n=17, perop 168+/-46, postop 104+/-51cm/sec, p<0.0005). 3) PDA Peak velocities of mitral valve were significantly decreased when compared perop. with postop. echocardiogram(n=29, perop 138+/-28, postop 111+/-19cm/sec, p<0.0005). Tricuspid valve velocities showed no significant changes between preop. and postop. echocardiogram (n=15, perop 47+/-12, postop 44+/-10cm/sec, p>0.05). Aortic valve velocities showed no significant changes (n=10, perop 134+/-23, postop 121+/-25cm/sec, p>0.05). Peak velocities of pulmonic valve were significantly decreased(n=28, perop 138+/-37, postop 107+/-27cm/sec, p<0.005). This study demonstrates that Doppler echocardiographic assessment of velovity changes are correlated with known hemodynamic data and also will be a good index in the evaluation of operation.