The Department of Defense (DoD) has been engaged in the development and deployment of the longitudinal health record (LHR). It has achieved remarkable technological success by handling vast amounts of patient data coming from clinical sites around the globe. Interoperability between DoD and VA has improved and this information sharing capability is expected to continue to expand as the defense health information system becomes an integral part of the national network. On the other hand, significant challenges remain in terms of user acceptance, ability to incorporate innovations, software acquisition methodology, and overall systems architecture.