The Volturno Plain is one of the largest alluvial plain of peninsular Italy. This area is characterized by both natural and human induced subsidence, and is and most susceptible to coastal hazards. The present study is based on post-processing, analysis and mapping of the available Persistent Scatterer interferometry datasets, derived from combination of both ascending and descending orbits of three different SAR satellite systems, during an observation period of almost two decades (June 1992 - September 2010). The main output of the research work is a map of the vertical deformation that provides new insights into the areal variability of ground deformation processes (subsidence/uplift) of Volturno plain over the last decades. Vertical displacement values derived by interferometric data post-processing show that the Volturno river plain is characterized by significant subsidence in the central axial sectors and in the river mouth area, whereas moderate uplift is detected in the eastern part of the plain. Other sectors of the study area are characterized by moderate subsidence and/or stability. We infer that the subsidence recorded in the Volturno plain is mainly a consequence of a natural process related to the compaction of the fluvial deposits that fill up the alluvial plain. Anthropic influence (e.g. water exploitation, urbanization) can be substantially regarded as an additional factor that only locally may enhance subsidence. The uplift imaged in the eastern sector of the plain can be related to tectonic activity. The study of subsidence in the Volturno plain is a valuable tool relevant for river flood analyses and coastal inundation hazard assessment addressed to risk mitigation.