The incidence, correlates, and prognostic implications of pulmonary hypertension (PH) are unclear in patients with severe aortic stenosis (AS). We studied 509 patients with severe AS evaluated for transcatheter aortic valve implantation (TAVI). Patients were divided into groups based on pulmonary artery systolic pressure (PASP): group I, 161 (31.6%) with PASP <40 mm Hg; group II, 175 (34.3%) with PASP 40 to 59 mm Hg; and group III, 173 (33.9%) with PASP ≥60 mm Hg. Group III patients were more symptomatic and had higher creatinine levels and higher left ventricular end-diastolic pressure. Transpulmonary gradient was >12 mm Hg in 17 patients (10.5%), 31 patients (17.7%), and 80 patients (46.2%) in groups I through III, respectively. In a median follow-up of 202 days (73 to 446) mortality rates were 35 (21.7%), 69 (39.3%), and 85 (49.1%) in groups I through III, respectively (p <0.001). Immediately after TAVI, in patients with PASP >40 mm Hg there was significant decrease in PASP (63.1 ± 16.2 to 48.8 ± 12.4 mm Hg, p <0.0001), which remained at 1 year (50.1 ± 13.1 mm Hg, p = 0.04). After surgical aortic valve replacement there was a significant immediate decrease in PASP (66.1 ± 16.3 to 44.7 ± 14.2 mm Hg, p <0.0001), which persisted at 3 to 12 months (44.8 ± 20.1 mm Hg, p <0.001). In patients who underwent balloon aortic valvuloplasty, PASP decreased immediately after the procedure (63.2 ± 14.8 to 51.8 ± 17.1 mm Hg, p <0.0001), yet at 3 to 12 months pressure returned to baseline levels (57.4 ± 17.0 mm Hg, p = 0.29). In conclusion, patients with severe AS have a high prevalence of PH, and in patients with severe AS increased PASP is associated with increased mortality. Surgical aortic valve replacement and TAVI are effective treatments for these patients and result in a significant PASP decrease.