e-Business in healthcare sector has been called e-Health, which is evolving into u-Health with advances of ubiquitous technologies. Seamless information sharing among health organizations is being discussed in many nations including USA, UK, Australia and Korea. Efforts for establishing the electronic health record (EHR) system and a nation-wide information sharing environment are called NHII (National Health Information Infrastructure) initiatives. With the advent of u-Health and progress of health information systems, information security issues in healthcare sector have become a very significant problem. In this paper, we analyze several issues on health information security occurring in u-Health environment and develop an information security standard for protecting health information. It is expected that the standard proposed in this work could be established as a national standard after sufficient reviews by information security experts, stakeholders in healthcare sector, and health professionals. Health organizations can establish comprehensive information security systems and protect health information more effectively using the standard. The result of this paper also contributes to relieving worries about privacy and security of individually identifiable health information brought by NHII implementation and u-Health systems.