Objective: The state of pulmonary vascular bed in congenital heart disease is the predictor of the patients clinical condition, prognosis and outcome of surgical intervention. This study aims to investigate the condition of pulmonary vascular bed analyzing pulmonary artery stiffness by means of Doppler echocardiography., Methods: Thirty-three patients (16 females, mean age 26+/-15 years) with various congenital heart diseases such as atrial septal defect (20 patients), ventricular septal defect (10 patients), patent ductus arteriosus (2 patients), atrioventricular septal defect (1 patient) were enrolled in this study. Systemic flow (Qs), pulmonary flow (Qp), systemic vascular resistance, pulmonary vascular resistance were calculated according to Fick method by using data obtained during left and right heart catheterization. Echocardiographically, pulmonary artery stiffness (PAS) was calculated by using maximal frequency shift (MFS) and acceleration time (AcT) of the pulmonary artery flow trace. PAS (kHz/sec)= MFS/AcT., Results: Invasively, the average Qp/Qs, mean pulmonary artery pressure, and pulmonary vascular resistance were found as 2.58+/-1.25, 25+/-20 mmHg, and 135+/-217 dyn.sec.cm-5, respectively. Echocardiographically, PAS was found to be 33+/-17 kHz/sec. Pulmonary artery stiffness was correlated with mean pulmonary artery pressure (r=0.63; p<0.001) and pulmonary vascular resistance (r=0.55, p<0.001), while no relation was found with Qp/Qs., Conclusion: Estimation of pulmonary artery stiffness by using pulmonary flow maximal frequency shift and acceleration time obtained by means of Doppler echocardiography may give us an idea about the state of pulmonary vascular bed.