To review the use of extracorporeal membrane oxygenation (ECMO) in severe paediatric pneumonia and evaluate factors that may affect efficacy of this treatment. Methods: Retrospective study of the ECMO database of a tertiary paediatric intensive care unit and chart review of all patients who were managed with ECMO during their treatment for severe pneumonia over a 23-year period. The main outcome measures were survival to hospital discharge, and ICU and hospital length of stay. We compared the groups of culture-positive versus culture-negative pneumonia, venoarterial (VA) versus venovenous (VV) ECMO, community- versus hospital-acquired cases, and cases before and after 2005. Results: Fifty patients had 52 cases of pneumonia managed with ECMO. Community-acquired cases were sicker with higher oxygenation index (41.5 ? 20.5 versus 26.8 ? 17.8; p = 0.031) and higher inotrope score [20 (5-37.5) versus 7.5 (0-18.8); p = 0.07]. Use of VA compared with VV ECMO was associated with higher inotrope scores [20 (10-50) versus 5 (0-20); p = 0.012]. There was a trend towards improved survival in the VV ECMO group (82.4 versus 62.9 ; p = 0.15). Since 2005, patients have been older [4.7 (1-8) versus 1.25 (0.15-2.8) years; p = 0.008] and survival has improved (88.2 versus 60.0 ; p = 0.039). Conclusions: Survival in children with pneumonia requiring ECMO has improved over time and is now 90 in the modern era. Risk factors for death include performing a circuit change [odds ratio (OR) 5.0; 95 confidence interval (CI) 1.02-24.41; p = 0.047] and use of continuous renal replacement therapy (OR 4.2; 95 CI 1.13-15.59; p = 0.032).