This paper describes some methodological aspects of the development of the Disas- ter Risk Index (DRI), a central component of the Reducing Disaster Risk report from the United Nation Development Programme (UNDP/BCPR 2004). The DRI aims to improve understanding of the relationship between development and disaster risk at the global level. The major assumption behind the index is that differences of risk levels faced by countries with similar exposures to natural haz- ards are explained by socio-economic factors, i.e. by the population vulnerability. The DRI allows the measurement and the comparison of relative levels of risk, ex- posure to hazard and vulnerability on a country by country basis. The DRI is also a contribution to a more quantitative evidence for planning and decision making in the field of risk reduction and management. This paper focuses on the evaluation of risk for four hazards (cyclones, droughts, earthquakes and floods). Starting from data on exposed population, as estimated us- ing Geographical Information System (GIS), a statistical analysis was carried out to identify the socio-economical indicators reflecting human vulnerability to hazards. To calibrate the risk model, past casualties recorded by the database EM-DAT from the Centre of Research on Epidemiology of Disasters (CRED)3 were used. The final outputs include a set of indicators for measuring levels of risk on a country by country basis, a global database on hazard frequencies, an evaluation of the popula- tion exposed and the identification of socio-economical parameters for estimating human vulnerability to natural hazards.