Two-dimensional and pulsed Doppler echocardiography were used to evaluate the function of right ventricule in 166 patients with essential hypertension and the results were compared with those of 79 normal subjects. The pulmonary artery peak flow velocity in 100 patients without left ventricular hypertrophy (LVH) had no significant difference with that of normal controls (0.65 +/- 0.17 vs 0.63 +/- 0.18, P greater than 0.05). The tricuspid early peak flow velocity (E) decreased (0.43 +/- 0.08 vs 0.46 +/- 0.12, P less than 0.01) but the late peak flow velocity (A) increased (0.30 +/- 0.09 vs 0.24 +/- 0.06, P less than 0.001). E/A reduced also (1.57 +/- 0.53 vs 2.02 +/- 0.78, P less than 0.01). The pulmonary peak flow velocity in 66 patients with LVH elevated markedly as compared with those without LVH (0.71 +/- 0.18 vs 0.65 +/- 0.17, P less than 0.001), A increased (0.34 +/- 00.10 vs 0.30 +/- 0.09, P less than 0.001) and E/A decreased (1.29 +/- 0.37 vs 1.57 +/- 0.53, P less than 0.001). The decrement of E/A correlated with the thickness of interventricular septum and the left ventricular mass (r = -0.68 and -0.60 respectively, P less than 0.01). The results show that the diastolic function of right ventricule was damaged in the early stage of essential hypertension but the systolic function remains unchanged. The diastolic function decreased and the systolic function increased further concomitantly with the development of LVH.