(CIT): NLM Informatics Lecture Series. Personal Health Records (PHRs) are gaining widespread attention as they take electronic form and potentially link to medical health records. An effective PHR will depend as much on the system and user interface as on the data in the records. This talk will report results from a project that aimed to develop an evidence-based framework for usability guidelines. A literature review, survey of existing PHR system features, design mockup, and four focused usability studies were completed and synthesized to yield three-dimensional usability guideline matrix that crosses PHR functionality, data types, and specific usability issues. Gary Marchionini is Cary C. Boshamer Professor in the School of Information and Library Science at the University of North Carolina at Chapel Hill, where he teaches courses in human-information interaction, interface design and testing, and digital libraries. He heads the Interaction Design Laboratory at SILS. He is the PI for a collaborative project funded by the National Cancer Institute to develop usability guidelines for personal health records.