Providers are now accessing EMRs built for desktop platforms on mobile devices. Survey findings indicate that these EMR systems built for desktop platforms may not be accessed using mobile devices due to limited screen real-estate, increased scrolling, inaccurate interactions, and constant zooming to read information. The purpose of this study was to conduct a usability test to compare user performance and satisfaction of a commercial EMR on a desktop and an iPad. Participants were 16 attending physicians who performed seven EMR tasks on both the desktop and the iPad. Participants took longer to complete the EMR tasks and were less efficient on the iPad than on the desktop. They perceived higher workload and rated the tasks as more difficult on the iPad. These results indicate that use of an interface created for a desktop computer on a mobile device may result in a less efficient and less satisfying user experience.