The pulsed doppler (P.D.) signals obtained in RVOT just below the pulmonary leaflets were used to calculate acceleration time (AcT), pre-ejection period (PEP) and their ratios. These indices were correlated in 31 patients (2 1/2-49 yrs. age) having varying cardiac lesions to Pulmonary arterial pressure (P.A.P) measured during cardiac catheterisation. The mean values of AcT for those with normal PAP was 137 +/- 19.9ms, as compared to 105 +/- 37 ms in those in whom PAP greater than 20mm of Hg. (t = 3.0.p less than .01). The P value was less than 0.001 when comparison was between normal PAP and severe PH. The ratios of PEP upon AcT was 0.87 +/- 0.18 for normal PAP, as compared to 1.39 +/- 0.74 in those with PH (t = 0.31, p less than 0.01). The PEP/AcT predicted systolic PAP 35.49 PEP/AcT + 3.22 (r = 0.77, p less than 0.001). The mean PAP was best predicted by 23.94 PEP/AcT + 2.44 (r = 0.75, p less than 0.001). The quantitative assessment showed presence of presystolic 'a' wave in all with normal PAP; this was absent in all the 9 patients with severe PH (MAPA greater than 40mm of Hg.). We conclude that noninvasively obtained P.D. derived indices can help accurately to predict PAP.