The aim of this study was to determine whether Doppler echocardiography could be used to estimate pulmonary artery pressure noninvasively. 153 patients were investigated by pulsed and continuous wave Doppler echocardiography, using right heart catheterization as the reference method. The pressure gradient (PG) between the right ventricle and right atrium was calculated by the modified Bernouilli equation by using the maximum velocity (Vmax) of the transtricuspid jet by Doppler-detected tricuspid regurgitation. Adding the estimated right atrial pressure (RAP), the systolic pulmonary artery pressure (PAPsyst) was calculated, which correlated well (r = 0,68) with the catheter values. Doppler estimation of mean pulmonary artery pressure (PAPmean) using the measuring of systolic time intervals, especially acceleration time (AT), has been shown to correlate moderate with measured values of PAPmean (r = -0,56). The findings of numererous studies were compared with the own data and analysed. In conclusion, Doppler echocardiography seems a useful semiquantitative noninvasive method for the prediction of pulmonary artery hypertension. Using a systematic examination from multiple transducer positions, especially by patients with COPD, angle correction, color-coded echocardiography, contrast enhancement of Doppler signals and measurement of systolic time intervals exactly in the right ventricular outflow tract or mean pulmonary artery should improve the feasibility and the accuracy of Doppler echocardiography.