Background Pulmonary hypertension (PHT) lacks community prevalence and outcome data. Objective To characterise minimum `indicative? prevalences and mortality data for all forms of PHT in a selected population with an elevated estimated pulmonary artery systolic pressure (ePASP) on echocardiography. Design Observational cohort study. Setting Residents of Armadale and the surrounding region in Western Australia (population 165 450) referred to our unit for transthoracic echocardiography between January 2003 and December 2009. Results Overall, 10 314 individuals (6.2 of the surrounding population) had 15 633 echo studies performed. Of these, 3320 patients (32 ) had insufficient TR to ePASP and 936 individuals (9.1 , 95 CI 8.6 to 9.7 ) had PHT, defined as, ePASP>40 mm Hg. The minimum `indicative? prevalence for all forms of PHT is 326 cases/100 000 inhabitants of the local population, with left heart disease-associated PHT being the commonest cause (250 cases/100 000). 15 cases of pulmonary arterial hypertension/100 000 inhabitants were identified and an additional 144 individuals (15 ) with no identified cause for their PHT. The mean time to death for those with ePASP >40 mm Hg, calculated from the first recorded ePASP, was 4.1 years (95 CI 3.9 to 4.3). PHT increased mortality whatever the underlying cause, but patients with PHT from left heart disease had the worst prognosis and those with idiopathic pulmonary arterial hypertension receiving disease-specific treatment the best prognosis. Risk of death increased with PHT severity: severe pulmonary hypertension shortened the lifespan by an average of 1.1 years compared with mild pulmonary hypertension. Conclusions In this cohort, PHT was common and deadly. Left heart disease was the most common cause and had the worst prognosis and treated pulmonary arterial hypertension had the best prognosis.