Pulmonary hypertension has been associated with poor outcome after liver transplantation. We assessed the diagnostic accuracy of Doppler echocardiography in detecting significant pulmonary hypertension. Seventy-four potential liver transplant candidates underwent Doppler echocardiography in which the systolic right ventricular pressure (RVsys) was used to estimate the systolic pulmonary artery pressure (PAsys). Group 1 included 39 consecutive patients with RVsys >/=50 mm Hg who underwent elective right heart catheterization. Group 2 consisted of 35 patients with RVsys <50 mm Hg in whom pulmonary artery pressures were measured at the beginning of the transplantation procedure. The accuracy of the estimates by Doppler echocardiography was assessed against measurements made by direct catheterization. Patients in groups 1 and 2 were comparable in their demographic and liver disease characteristics. There was a strong correlation between RVsys by Doppler echocardiography and PAsys by right heart catheterization (r =.78, P <.01). Of the 39 patients in group 1, 29 (72%) had at least moderate pulmonary hypertension (mean pulmonary artery pressure [MPAP] >/=35 mm Hg), including 12 (30%) with severe pulmonary hypertension (MPAP >/=50 mm Hg). Only 1 of the group 2 patients had MPAP >/=35 mm Hg. Thus, in the diagnosis of moderate to severe pulmonary hypertension, the sensitivity of echocardiography was 97% and specificity was 77%. Doppler echocardiography is an accurate screening test to detect moderate to severe pulmonary hypertension. We advise that liver transplant candidates with RVsys >/=50 mm Hg undergo right heart catheterization to fully characterize pulmonary hemodynamics.