In the new paradigm of flood defence, the control of flooding by technical means is supported by an emphasis on the reduction of vulnerability to flooding by economic, social and environmental means. The aim of the present work was to assess the vulnerability of basic urban units (BUUs) located in the headwater basins of Slovakia. Vulnerability was expressed in terms of proxy variables. Using a combination of these variables, specific indices were established. These indices represented the potential for susceptibility to damage, resistance to flooding and resilience after flooding of the social and economic systems in these BUUs. The assessment of vulnerability was based on an application of the multi-atribute decision-making approach. The overall vulnerability of a BUU was calculated via a summation of the specific vulnerability indices. Using visualisation in GIS, the BUUs were grouped into three classes, of low, medium and high vulnerability. Second, evaluation of BUUs from the point of view of expected negative consequences of flooding was done.