Plasma amino acid concentrations (aminogram) show distinct patterns under various pathologic conditions. However, the plasma aminogram pattern in patients with pulmonary hypertension (PH) has not been elucidated. We sought to examine whether an aminogram could be predictive of clinical severity in patients with PH. We attained fasting plasma aminograms for 140 patients with PH and then compared the patient plasma amino acid levels with those of age- and gender-matched healthy control subjects. Aminograms revealed that the plasma concentrations of many amino acids were significantly different between patients with PH and healthy control subjects.