In 11 patients with primary pulmonary hypertension (PPH) and 16 with secondary pulmonary hypertension due to left-to-right shunt (SPH), echocardiographic and morphological features of the pulmonic valve were studied. Mean ages of these patients were 27 and 31 years, respectively. The echo intensity of the pulmonic leaflet was graded as either "strong" or "not strong" by comparison with the adjacent tissue. In the PPH group, the valve echo was "not strong", while it was "strong" in the majority of the cases of SPH. In autopsy, there were no morphological changes in the pulmonic valves in the former, while these valves were definitely hypertrophic in the latter. The average thicknesses of the valve edges in the two groups of patients were 0.5 and 1.6 mm, respectively. The results suggest that the different echo intensities reflect the morphological differences of the pulmonic valve; and this provides a diagnostic value for differentiating the two conditions.