The Nationwide Health Information Network allow for the secure exchange of Electronic Health Records over the Internet. The Department of Veterans Affairs, Department of Defense, and Kaiser Permanente, participated in an implementation of the NwHIN specifications in San Diego, California. This paper focuses primarily on patient involvement. Specifically, it describes how the shared patients were identified, were invited to participate and to provide consent for disclosing parts of their medical record, and were matched across organizations. A total 1,144 were identified as shared patients. Invitation letters containing consent forms were mailed and resulted in 42% participation. Invalid consent forms were a significant issue (25%). Initially, the identity matching algorithms yielded low success rate (5%). However, elimination of certain traits and abbreviations and probabilistic algorithms have significantly increased matching rate. Access to information from external sources better informs providers, improves decisions and efficiency, and helps meet the meaningful use criteria.