Benfluorex was marketed in France until 2009, despite its similar pharmacological properties with fenfluramine and its derivatives known to be a cause of pulmonary arterial hypertension (PAH). The aim of this study is to report clinical and haemodynamic characteristics for patients suffering from pulmonary hypertension (PH) associated with benfluorex exposure that had been identified by the French PAH Network. 85 cases of PH associated with benfluorex exposure were identified by the French PAH Network from June 1999 to March 2011. Of these, 70 patients had confirmed pre-capillary PH. The median duration of exposure was 30 months, with a median of 108 months between start of exposure and diagnosis of the pulmonary vascular disease. 33% of all patients also had prior exposure to fenfluramine or dexfenfluramine, and an additional risk factor for PH was identified in 20 (30%) out of 70 patients with pre-capillary PH. A quarter of patients in this current series showed coexisting PH and mild-to-moderate cardiac valve involvement. The results of our study, together with the accumulated data regarding the known toxic effects of fenfluramine and dexfenfluramine, strongly suggest that benfluorex exposure is a potent trigger for PAH.