Antisynthetase syndrome is characterised by the association of interstitial lung disease and myositis with different anti-tRNA-synthetase antibodies. The occurrence, aetiology and prognosis of pulmonary hypertension have not yet been evaluated. Among 203 consecutive patients, transthoracic echocardiogram and right heart catheterisation results were retrospectively analysed in the light of clinico-biological, morphological and functional parameters. Definitions of pulmonary hypertension were based on the European Society of Cardiology/European Respiratory Society 2009 guidelines, with severe pulmonary hypertension being defined by a mean pulmonary arterial pressure >35 mmHg. Pulmonary hypertension was suspected by transthoracic echocardiogram in 47 (23.2%) cases, corresponding to pulmonary hypertension "possible" (n=27, 13.3%) or "likely" (n=20, 9.9%). Right heart catheterisation was performed in 21 patients, excluding pulmonary hypertension in five and confirming pre-capillary pulmonary hypertension in 16 (7.9%). Although related to interstitial lung disease in all cases, pre-capillary pulmonary hypertension was severe in 13 (81.3%) patients (mean ± sd pulmonary arterial pressure 46 ± 9 mmHg), frequently associated with low cardiac index (mean ± sd 2.3 ± 0.8 L · min(-1) · m(-2)) and high forced vital capacity/diffusing capacity of the lung for carbon monoxide ratio (2.5 ± 0.6). Pulmonary hypertension was significantly associated with a lower survival rate (p<0.001), with a 3-year survival rate of 58%. The occurrence of pulmonary hypertension in antisynthetase syndrome is significant and dramatically worsens the prognosis. Although systematically associated with interstitial lung disease, pulmonary hypertension was usually severe, suggesting a specific pulmonary vascular involvement.