The Chapter considers the main threats to information security in health care. The protection of the electronic health information from unauthorized access, use, disclosure, disruption, modification or destruction is discussed. The key concepts examined are: confidentiality – electronic health information must be preserved by authorized restrictions on access and disclosure, not making available or disclosed to unauthorized persons and processes; integrity – electronic health information must be guarded by improper modification or destruction; availability – electronic health information must be accessible and usable upon demand by an authorized person or process. Real life examples are discussed. The information threat scheme and protection mechanisms are represented.