Medical errors in the neonatal intensive care unit (NICU) are common and can result in significant patient harm. This prospective observational study conducted at 10 NICUs in France found that approximately 41% of the 1,822 errors (among 1,019 patients) were disclosed to the patient’s parents. Providers cited parental absence (i.e., the error occurred overnight) and perceived lack of serious consequences for the infant as the most frequent reason for non-disclosure.