Case 1, a 28-year-old woman (third daughter of Case 2) delivered her first child in September 2000, but leg edema and dyspnea on exertion appeared the following January. At the time of our first examination of the patient in May 2001, a chest X-ray showed cardiomegaly and pulmonary artery enlargement. Echocardiography demonstrated enlargement of the right ventricle and small left ventricular dimensions, and an electrocardiogram revealed right ventricle hypertrophy. After perfusion-ventilation lung scintigraphy and cardiac catheterization, she was diagnosed as having primary pulmonary hypertension (PPH). Although she was discharged with prescriptions for a diuretic, warfarin and beraprost sodium, she died of a pulmonary hypertensive crisis twenty days after readmission. Case 2, a 60-year-old woman (mother of Case 1) developed the same symptoms as those in Case 1, in May 2001, but recovered after medication. PPH is a rare disease and only a few familial cases are reported. In this family, the eldest daughter of Case 2 had also died of pulmonary hypertension ten years ago, several months after her first delivery. In contrast to the daughters, the mother's symptoms developed gradually.