<p>Pediatric populations are uniquely vulnerable to the usability and safety challenges of electronic health records (EHRs), particularly those related to medication, yet little is known about the specific issues contributing to hazards. To understand specific usability issues and medication errors in the care of children, we analyzed 9,000 patient safety reports, made in the period 2012-17, from three different health care institutions that were likely related to EHR use. Of the 9,000 reports, 3,243 (36&nbsp;percent) had a usability issue that contributed to the medication event, and 609 (18.8&nbsp;percent) of the 3,243 might have resulted in patient harm. The general pattern of usability challenges and medication errors were the same across the three sites. The most common usability challenges were associated with system feedback and the visual display. The most common medication error was improper dosing.</p>