The incidence and types of adverse events can vary widely across different clinical settings. This retrospective cohort study used a novel trigger tool to classify adverse events in the pediatric intensive care unit, with a particular focus on medication errors and patient-level risk factors for errors. The overall incidence of errors was similar to that found in prior studies, with surgical patients and intubated patients being most vulnerable to error. Medication errors were the most common type of error in this study, and prior research in the pediatric ICU setting has documented the benefit of computerized provider order entry for preventing medication prescribing errors, an example of which is discussed in an AHRQ WebM&M commentary.