Pulmonary hypertension (PH) is a heterogeneous condition. To date, no registry data exists reflecting the spectrum of disease across the five diagnostic groups encountered in a specialist referral centre.Data was retrieved for consecutive, treatment-naïve cases diagnosed between 2001 and 2010 using a catheter-based approach. 1,344 patients were enrolled, with a mean follow-up of 2.9 yrs.The 3-yr survival was 68% for pulmonary arterial hypertension (PAH), 73% for PH associated with left heart disease, 44% for PH associated with lung disease (PH-lung), 71% for chronic thromboembolic PH (CTEPH) and 59% for miscellaneous PH. Compared with PAH, survival was inferior in PH-lung and superior in CTEPH (p,0.05). Multivariate analysis demonstrated that diagnostic group independently predicted survival. Within PAH, Eisenmenger's survival was superior to idiopathic PAH, which was superior to PAH associated with systemic sclerosis (p,0.005). Within PH-lung, 3-yr survival in sleep disorders/alveolar hypoventilation (90%) was superior to PH-lung with chronic obstructive pulmonary disease (41%) and interstitial lung disease (16%) (p,0.05). In CTEPH, long-term survival was best in patients with surgically accessible disease undergoing pulmonary endarterectomy.In this large registry of consecutive, treatment-naïve patients identified at a specialist PH centre, outcomes and characteristics differed between and within PH groups. The current system of classification of PH has prognostic value even when adjusted for age and disease severity, emphasising the importance of systematic evaluation and precise classification.