Primary pulmonary hypertension (PPH) is one of rare and fatal vascular disorder. The exact mechanisms for the increased pulmonary vascular resistance and pressure in PPH are unknown. The disease is advanced pro-gressively and patients naturally die within three years after the initial diagnosis. PPH is characterized with mean pulmonary artery pressure over 25-30 mmHg and intractable hypertension despite any intensive therapeutic maneuvers. Associated congenital anomaly is very rare. We report a 19 year-old female patient who diagnosed as PPH 10 years ago and suffered from severe pulmonary hypertension (100 mmHg of pulmonary arterial pressure) with the congenital absence of inferior vena cava. Her venous blood from lower body was drained through azygous vein into superior vena cava.