Pulmonary arterial hypertension (PAH) is a classical complication of connective tissue diseases (CTD), particularly in systemic sclerosis (SSc), systemic lupus erythematous (SLE) or mixed connective tissue diseases (MCTD). The prevalence of PAH in SSc, as measured by right heart catheterization (RHC), is estimated between 7.85 to 13%. The detection of PAH in SSc is based on trans-thoracic echocardiography. Early detection in pulmonary hypertension is the best way to improve the survival in these diseases. In the DETECT study, 19% of high-risk PAH patients with SSc (SSc diagnosed less than 3 years before and DLco<60% predicted) have PAH as measured by RHC. Specific treatments for PAH are less efficient in PAH related to SSc than in idiopathic PAH. The main characteristic of PAH related to CTD other than SSc is a good response to immunosuppressive treatment, with an improvement in 50% of cases in SLE or MCTD. The prognosis of PAH associated with CTD seem to improve with the diversification of treatments available, but remains reserved. Therapeutic combinations and new molecules should allow to improve the prognosis.