The assessment of the seismic risk of existing dams is a complex topic, which is of considerable importance in Italy considering the high seismic risk in the country and the extent of the potential consequences that could arise from the uncontrolled release of the huge volume of water considered in a highly developed context such as Italy. The assessment of seismic risk requires complex studies which include the definition of the risk in terms of the probability of occurrence of a seismic event, the structural vulnerability of the dam in the face of this event and the consequences of the flooding of the downstream areas caused by its possible break. When the number of cases to be examined is considerable, it can be very useful to have rapid methods available that allow us to identify, in the first instance, an order of priority for subsequent investigations. For this reason, the IRIS tool (acronym for Seismic Risk Indices for concrete dams) was developed: it is a software created as a plug-in for the software QGIS (an open source GIS), capable of classifying the concrete dams in terms of seismic risk, thus providing support to managers and authorities in identifying priorities. The tool, which provides a qualitative, preliminary and relative estimate of risk, uses rapid criteria and methods which, starting from a few easily available representative parameters, define appropriate indices associated with seismic hazard, structural vulnerability and consequences.