Pulmonary arterial hypertension (PAH) is characterized by progressive obliteration of the small pulmonary vascular bed as a result of vascular proliferation and remodelling of the vessel wall leading to permanently increased pulmonary vascular resistance and elevated pulmonary artery pressures, which result in right heart failure and premature death. Pathologic processes behind the complex vascular changes associated with PAH include vasoconstrictor/vasodilator imbalance, thrombosis, misguided angiogenesis and inflammation. Besides idiopathic PAH, it can also occur in association with portal hypertension, HIV infection, congenital cardiac left-to-right shunts and connective tissue diseases (CTD). Unfortunately, despite recent major improvements in PAH treatment, no current therapy can yet cure this devastating condition. This review will briefly highlight epidemiology, pathogenesis, and diagnostic and treatment options known so far for PAH occurring in connection with CTD.