The development of pulmonary arterial hypertension after bone marrow transplantation (BMT) is a rare but serious complication. In this case report, we presented the development of pulmonary arterial hypertension in a 22-year-old woman who underwent BMT due to aplastic anemia. Her symptoms on admission included shortness of breath, palpitations and fatigue. Pulmonary hypertension was classiﬁed with right heart catheterization as pul monary arterial hypertension. The patient's laboratory, echocardiographic and hemodynamic ﬁndings improved with pulmonary arterial hypertension-speciﬁc treatment. Pul monary arterial hypertension should be considered in the diﬀer ential diagnosis of BMT patients with 'unexplained' hypoxemia or respiratory distress.