During the last 50 years natural and social disasters have increased 250%, affecting at least 800 million people. The causes of these disasters are various and most of them are not predictable. A successful strategy is a well planned medical response. The use of Field Hospitals 'FH' specialized for the disasters and planned to guarantee high technical and medical standards is a fundamental component in reducing mortality. The DSS, 'Decision Support Model', has allowed the planning of Field Hospitals according to the disaster typology and to the disaster area taking into account the number of people involved and the local health system capacity. The DSS specifies also Field Hospital technical requirements and technological support.