Noninvasive prediction of pulmonary arterial pressure is of paramount importance in heart disease. To estimate pulmonary arterial pressure, several echocardiographic techniques, including abnormal pulmonary valve motion, prolongation of RV preejection period/RV ejection time ratio and contrast echocardiography have been proposed. Recently Doppler echocardiography has been known to detect intracardiac blood quantitatively. For assessment of the benefit of several indices by Pulsed Doppler echocardiography for mean pulmonary arterial pressure, 22 patients(mean pulmonary pressure> or =20mmHg; 11, <20mmHg; 11) were compared with the mean pulmonary arterial pressure by cardiac catheterization. In comparison of mean pulmonary arterial pressure(MPAP); 1) Right preejection period / RV ejection time RPEP/RVET;r=0.278 2) Right preejection period / Acceleration time RPEP/AT : r=0.654 3) Acceleration time(AT) AT=-1.55(MPAP)+154.37(r=-0.763) AT=-92.99(log MPAP)+239.41(r=-0.752) AT is less than 105 msec in 9 or 11 pulmonary hypertension and one of 11 normal individual. 4) Acceleration time/ RV ejection time AT/RVET=-136.36(MPAP)+83.31(r=-0.817) AT/RVET=-0.29(log MPAP)+0.81(r=-0.803) 5) (Right preejection period+Decceleration time) / AT (RPEP+DT)/AT=9.6(MPAP)-0.16(r=0.806) (RPEP+DT)/AT=3.86(log MPAP)-2.46(r=0.789) In conclusion AT/RVET, (RPEP+DT)/AT and Acceleration time of 105 msec are valuable indices to estimate mean pulmonary arterial pressure by Pulsed Doppler echocardiogram.