[Background] Pulmonary wedge pressure(PWP) is an established index of cardiac function and an essential component in the management of critically ill patients. There are several echocardiographic parameters reported to be reliable factors to estimate the PWP. Recently, B-type natriuretic peptide(BNP) is also reported to increase in systolic and diastolic heart failure. However, whether the value of BNP can predict PWP is unclear. [Purpose] We investigated whether these parameters including BNP could predict PWP or not. [Methods] We prospectively studied 30 consecutive critically ill patients in intensive care unit. Several echocardiographic Doppler parameters including especially deceleration time(DT) of pulmonary venous diastolic flow were obtained from bedside transesophageal and transthoracic pulsed Doppler echocardiography. Simultaneously, serum BNP level and PWP estimated by using Swan-Ganz catheter were obtained, respectively. [Results] All echocardiographic Doppler parameters and BNP were not found to be related to PWP. And DT of pulmonary venous flow was not related to estimate the PWP, either. However, in group of high BNP levels (>=300pg/ml) a strong positive correlation was observed between PWP and BNP (r=0.82, p=0.012). [Conclusion] In selected cases of critically ill patients (BNP level >=300pg/ml) BNP level might be very useful factor to estimate the PWP.