The study develops a geological/geotechnical model of the filling of the buried Tiber River valley in the area of Rome. The approach has been multidisciplinary: the fill sediments have been analysed in detail and are given on a cross section based on either the observations of 57 borehole cores and/or the laboratory tests on various types of samples. Information regarding the geology, geomorphology, climate, hydrographic network, urban development and history of the Rome area has been used to interpret this section and to extrapolate the data to the historical centre of Rome in order to formulate the model. The proposed model is a global forecasting rather than a detailed one and can be used as a starting point for projects to be conducted in the Tiber River alluvium or for defining a specific approach to technical problems linked to these projects