This paper presents methodology and results of seismic vulnerability analyses performed in flood expansion areas of Parma River, tributary streams of the Po River in Emilia-Romagna (Italy). The proposed methodology included the following steps: collection of the pre-existing information and geologic map; performing of in-situ investigations and geotechnical laboratory tests on the collected soil samples; definition of the geologic-geophysical and geotechnical models; individuation of the expected seismic inputs; analyses of Local Seismic Response; identification of a number of significant sections; analyses of slope stability. The results obtained are discussed in the paper in order to illustrate how the methodology employed enables definition of the seismic vulnerability of the flood expansion area and allows to give indications regarding its future use. The proposed study points out that the flood expansion area has a level of safety adequate for guaranteeing seismic stability taking into account the rules of Italian Ministerial Decrees 14.01.2008 and 24.03.1982. It is therefore possible to consider the area suitable also as a reservoir basin and no intervention is required other than normal monitoring and maintenance.