This report documents the usability testing evaluation of the 2018 National Survey of Children’s Health. The PC-version and mobile-optimized version of the survey were pretested in both English and Spanish. The 12 English-speaking and 5 Spanish-speaking participants found similar problems. All participants found the questionnaire long with many questions seemingly unnecessary for healthy, typically developing children. While all English-speaking participants finished the survey, only one Spanish-speaking participant was able to finalize and submit the entire survey within the 90-minute usability session. The design of the page for listing the children in the household was complex. Participants did not know which button to select to add a child’s name. For a few questions, participants could answer either in metric or U.S. customary units (for example, height was measured in feet or meters), or in months or years. Participants were supposed to select one of the units to answer.  However, participants answered using all the options available to enter information. For example, for children’s height, participants provided information in both measurement systems (meters and feet) and for age, they entered information in both years and months. Participants did not realize they needed to choose one option over the other. The spacing and size of response fields and response choices when accessed on iPhones was poor, with small and closely spaced radio buttons, which when selected did not appear selected. Participants did not use or understand the progress bar at the bottom of the screen on PCs. Like other surveys, the review screen was not helpful and not used by any participants to review their answers. In addition, many Spanish speakers did not find the language toggle to Spanish on the first page.