The electronic personal health record (PHR) has been championed as a mediator of patient-centered care, yet its usability and utility to patients, key predictors of success, have received little attention. Human-centered design (HCD) offers validated methods for studying systems effects on users and their cognitive tasks. In HCD, user-centered activities allow potential users to shape the design of the end product and enhance its usability. We sought to evaluate the usability and functionality of HealthView, the PHR of the Duke University Health System, using HCD methods. Study participants were asked to think aloud as they carried out tasks in HealthView. They then completed surveys and interviews eliciting their reactions to the web portal. Findings were analyzed to generate redesign recommendations, which will be incorporated in a future release of HealthView.