Primary pulmonary hypertension is a condition characterized by sustained elevations of pulmonary artery pressure without demonstrable cause. It is incurable and progressive clinical entity. The incidence has been estimated at approximately 1 to 2 cases per million people in the general population. The maternal mortality of primary pulonary hypertension in pregnancy was said to be 30% and the first month after delivery represents the period of highest risk. We experienced a 27-year-old women with primary pulmonary hypertension diagnosed in postpartum period. She was transferred from the department of obstetrics to internal medicine due to dyspnea on the first day of postpartum. She was diagnosed by perfusion lung scan, chest CT and confirmed by echocardiography. This diagnosis were supported by findings of pulmonary angiogram and cardiac catheterization. Initially she was treated with diuretics, aspirin and anticoagulant therapy, and as a result of the treatment, her symptoms improved. However after 8months has elapsed, exertional dyspnea was worsening. Thus she was treated with calcium channel blocker, aspirin and diuretics and was followed at 1 month interval on the outpatient clinics.