Triggers, clinical signals that may indicate adverse events (AEs), have been used to screen for errors in a variety of clinical settings. This AHRQ–funded study used methodology similar to a prior study in adult intensive care unit patients to develop a chart-based set of triggers for error identification in the neonatal intensive care unit (NICU). Through an expert consensus process, 17 triggers were identified and used to screen charts from 15 NICUs. Adverse events were relatively common, occurring at a rate of 0.74 per patient, most of which were preventable. The trigger tool appeared to be a sensitive (though nonspecific) method for identifying AEs. Use of this chart-based review process may help identify specific patient populations at high risk for AEs and help target patient safety efforts.