Patients with moderate and severe pulmonary hypertension have a very high mortality rate when undergoing orthotopic liver transplantation. Because nitric oxide has been successful in reducing pulmonary artery pressures in certain patients with pulmonary hypertension, the efficacy of NO inhalation (40 and 80 ppm) in 4 patients with pulmonary hypertension associated with liver disease was determined. No clinically significant changes in pulmonary artery pressures or other hemodynamic parameters were observed using either concentration of NO. In conclusion, no pulmonary vasodilatory response from inhalation of NO in 4 patients with severe liver disease and pulmonary hypertension was found.