Right ventricular dysfunction (RVD) is an important determinant of functional status and survival in various diseases states. Data are sparse on the epidemiology and outcome of patients with severe RVD. This study examined the characteristics, aetiology, and survival of patients with severe RVD. Retrospective study of consecutive patients with severe RVD diagnosed by transthoracic echocardiography (TTE) between 2011 and 2015 in a single tertiary referral institution. Patients with prior cardiac surgery, mechanical assist devices, and congenital heart disease were excluded. Primary endpoint was all-cause mortality. In 64 728 patients undergoing TTE, the prevalence of ≥mild RVD was 21%. This study focused on the cohort of 1299 (4%) patients with severe RVD; age 64 ± 16 years; 61% male. The most common causes of severe RVD were left-sided heart diseases (46%), pulmonary thromboembolic disease (18%), chronic lung disease/hypoxia (CLD; 17%), and pulmonary arterial hypertension (PAH; 11%). After 2 ± 2 years of follow-up, 701 deaths occurred, 66% within the first year of diagnosis. The overall probability of survival at 1- and 5 years for the entire cohort were 61% [95% confidence interval (CI) 58-64%] and 35% (95% CI 31-38%), respectively. In left-sided heart diseases, 1- and 5-year survival rates were 61% (95% CI 57-65%) and 33% (95% CI 28-37%), respectively; vs. 76% (95% CI 68-82%) and 50% (95% CI 40-59%) in PAH, vs. 71% (95% CI 64-76%) and 49% (95% CI 41-58%) in thromboembolic diseases, vs. 42% (95% CI 35-49%) and 8% (95% CI 4-15%) in CLD (log-rank P < 0.0001). Presence of ≥moderate tricuspid regurgitation portended worse survival in severe RVD. One-year mortality of patients with severe RVD was high (∼40%) and dependent on the aetiology of RVD. Left-sided heart diseases is the most common cause of severe RVD but prognosis was worst in CLD.