The prevalence of chronic lung disease increases with advancing age. The purpose of this study was to detect latent pulmonary hypertension noninvasively in elderly patients with chronic lung disease. The changes of flow-velocity by passive leg raising were assessed using pulsed Doppler echocardiography in the right ventricular outflow tract in 19 patients with chronic lung disease and 13 normal healthy subjects. Pulmonary artery pressure was measured simultaneously using a thermodilution cardiac output catheter. In patients with chronic lung disease examined at rest, we found pulmonary hypertension in seven, and none in 12. The normal pattern observed at rest changed to pulmonary hypertension pattern after leg raising in six out of the 12 patients. Pulmonary arterial catheterization confirmed the data obtained by pulsed Doppler echocardiography. Some elderly patients with chronic lung disease have latent pulmonary hypertension which can be detected noninvasively by analyzing the changes of flow velocity profiles in the right ventricular outflow tract by passive leg raising.