The European Federation for Medical Informatics has established itself as a regional body coordinating activity in medical informatics. The Congress in Toulouse, MIE-81, from 9 – 13 March 1981, is the third congress in the ser ies following MIE-78 in Cambr idge, and MIB-79 in Berlin with a gap during 1980 for the world congress MEDINFO-80 in Tokyo. The rationale behind all these congresses is the scientific need to share results and ideas and the educational need to train a wide variety of professional staff in the potential of health care and medical informatics. All the caring professions are involved, doctors, scientists, nurses, para-medical staff, administrators, health care planners, community physicians, epidemiologists, statisticians, operations analysts together with specialists from the computing profession dealing with system analysis, hardware, software, languages, data-bases and the marketing of systems. Medical Informatics is a very wide subject with ramifications throughout the health care and preventive services; it offers a key to the monitoring and improvement of patient care and to the provision of a healthier environment. The collection and evaluation of relevant data improves our understanding of the ways in which health care is provided while the availability of cheaper computer hardware and more versatile software enables us to design and implement more revealing and intelligent medical systems. Even though typical systems take a substantial amount of time to design, implement and evaluate, there is the continuing need for informaticians to assess the current state of developmen.