Primary pulmonary hypertension (PPH) is a rare disease of the pulmonary vasculature which largely affects young women and usually runs a rapidly fatal course. Therapeutic trial has continued to reduce the vascular obstruction, lowering the pulmonary vascular pressure and resistance. However, because the etiology is still unknown, therapy is empiric and most patients are clinically fragile, many physicians refrain from intervening. We analyzed clinical and hemodynamic features of 11 PPH patients, confirmed by echocardiogram and cardiac catheterization, and reviewed the literature. The results were followings: 1) Among 11 patients, 5 were male and 6 female, male to female ratio was 1:1.2. Age ranged from 16 and to 52 years, the mean age was 30.4 years. 2) One patient was associated with scleroderma, the other one case was combined with systemic lupus erythematosus and in two patients, including the latter case, the ANA titer was more than 1:80. 3) Clinical features comprised dyspnea in all, chest pain in 54.5%, palpitation in 45.5%, cyanosis and orthostatic dyspnea in 27.3%, and syncope in 18.2%, respectively. 4) Pulmonic second heart sound was accentuated in all patients. Ejection systolic murmur was heard at pulmonic area in 72.7% and diastolic murmur in 45.5%. Pretibial pitting edema in 36.4%, hepatomegaly and superficial neck vein distension in 27.3% were noted. 5) Right ventricular hypertrophy, right axis deviation, right atrial enlargement and right bundle branch block were common EKG findings. In the chest roentgenogram, prominent pulmonary conus was noted in all and cardiomegaly 9 cases. 6) Echocardiogram showed right ventricular dilatation in all, and the ratio of the thickeness of the interventricular septum and left ventricular posterior wall was 0.88-1.50. Midsystolic notching was demonstrated in 6 patients and abnormal interventricular wall motion in 5. 7) hemodynamic data revealed normal pulmonary wedge pressure or left atriae pressure (ranged 4-14: mean; 8.5+/-3.9mmHg). Meanwhile, pulmonary artery pressure highly elevated: systolic pressure ranged between 60-180 (mean; 107.5+/-30mmHg, diastolic pressure 25-90 (mean; 47.9+/-19.6)mmHg and mean pulmonary artery pressure 40-120(mean; 66.5+/-24.7)mmHg. Pulmonary vascular resistance also elevated between 465-3167 (mean; 1209+/-797) and Rp/Rs was elevated in all. Arterial oxygen desaturation was noted 3 patients.