The purpose of our study was to examine the reliability of nurse reports of adverse events related to procedural sedation in children. A descriptive, correlational design was used to analyze for inter-rater agreement between prospective adverse event reporting and that identified on independent review of the medical record. All sedation documentation at a pediatric hospital over one calendar year was reviewed, and inter-rater reliability of reporting was analyzed using K statistics. Five thousand forty-five sedation documentation records were reviewed. An adverse event rate of 6.52% was identified: 1.92% of adverse events were serious, and 4.60% were minor. Although overall agreement between nurse reports and independent review was greater than 99%, subanalysis suggested greater agreement for serious events than for minor ones (K values: 0.85 vs 0.49, P < .01). The results of our study revealed that minor adverse events associated with procedural sedation were under-reported, despite clear perianesthesia documentation in the medical record that an event had occurred. Improved education for perianesthesia nurses regarding the importance of monitoring both for serious and minor adverse events will help to identify opportunities to improve sedation protocols.