Since July 1992, the WHO Regional Office for Europe has been using epidemiological and public health assessment techniques to guide its interventions in the crisis in the former Yugoslavia. WHO field operations have evolved into the largest emergency relief operation ever undertaken in the European Region. The WHO programme of humanitarian assistance focuses on five major areas: public health, equipment, supplies and logistic support, support to war victims, primary health care for refugees and rehabilitation of the health care system. The main thrust of the programme is to implement the public health measures required for survival. The first step is to provide health intelligence for international humanitarian assistance programmes through health and nutrition monitoring. This leads to targeted intervention. While involved in all aspects of relief, WHO clearly justifies its presence by its technical focus, bringing its network of expertise and experience to bear on the assessment of need and the coordination of intervention. Three examples of this approach are given: the nutrition programme, which includes emergency food aid and health and nutrition monitoring, the winter protection programme in Bosnia and Herzegovina, and the medical kit programme, involving the design and use of special kits to cover basic emergency needs for medical supplies to the maximum number of people. In the former Yugoslavia, the WHO Regional Office for Europe has concentrated on technical situation analysis and sound public health grounding to guide and direct intervention.