For a start this paper contains a short historical overview showing important steps in the ICT development in Danish healthcare with emphasis on the data network and communications. In 1988 the development of a national healthcare data network began. It was initiated with experiments with an EDI message for prescriptions, exchanged between GPs and pharmacies. Later more parties, i.e. hospitals, laboratories, municipalities etc. were connected to the network. In the year of 2000 a great part of the paper based messages exchanged between the parties were developed as EDI messages, standardized and in daily use by all parties. The paper ends by describing the development since year 2000, when the strategy was supplemented with new methods, where the exchange mechanism was changed from sending data between parties to sharing data through central national repositories. The role of legislation in the field is discussed.