Pulmonary hypertension is a serious but often overlooked complication in collagen vascular disease. The understanding of the development of pulmonary hypertension has increased substantially during the last years. Abnormal proliferation of pulmonary vascular cells is now being regarded as a predominant process leading to pulmonary vascular obliteration. Medical therapy focuses on prostacyclin treatment, which has been shown to improve exercise capacity and haemodynamic variables in patients with several collagen vascular diseases and pulmonary arterial hypertension. Continuous intravenous prostacyclin remains the standard treatment of associated pulmonary hypertension but less invasive alternatives such as subcutaneous treprostinil, oral beraprost or aerosolized iloprost, as well as, novel substances such as endothelin receptor antagonists may be appropriate for selected patients.