['Acute kidney injury (AKI) is associated with significant morbidity and mortality in patients with critical illness; however, its impact on children with trauma is not fully unexplored. We hypothesized that AKI is associated with increased in-hospital mortality.', 'A retrospective review of consecutive mechanically ventilated patients aged 0 years to 20 years from 2004 to 2007 with trauma hospitalized at our institution was performed. Univariate and multivariate analyses were performed to identify whether AKI was a risk factor for hospital mortality.', 'Eighty-eight patients met inclusion/exclusion criteria. The study cohort included 58 (66%) males with mean (SD) age of 11.6 (5.5) years (median, 13.25; range, 0.083-19.42 years) and mean (SD) Pediatric Expanded Logical Organ Dysfunction score of 24 (11) (median, 22; range 2-51). Mean pediatric intensive care unit length of stay (median, 11; range, 4-43) and duration of mechanical ventilation (median, 9; range, 3-34), was 13.5 (8.2) days and 11.2 (7.2) days, respectively. The mean (SD) Injury Severity Score for the cohort was 28 (14). Pediatric RIFLE identified those at risk (R), those with injury (I), or those with failure (F) in 30 (51%), 10 (17%), and 12 (21%) patients, respectively. There was a 10% (3 of 30 patients) mortality rate in those at risk, 30% (3 of 10 patients) in those with injury, and 33% (4 of 12 patients) in those with failure. AKI (injury and failure groups) was significantly associated with increased in-hospital mortality.'] Is acute kidney injury associated with increased in-hospital mortality in mechanically ventilated children with trauma?