This work deals with the characterization of the materials used for the construction of the Roman bridge known as the Pont del Diable1 in Martorell-Castellbisbal (Catalonia, Spain). The Romans used the most easily available materials they could find close to the bridge site. Four different lithological types were identified in the material used to build the Roman part of the bridge: the red and white Buntsandstein sandstones of the Triassic formation from the Deveses stream (between Martorell and Castellví de Rosanes), the yellow bioclastic calcarenites from the Miocene formation located in Can Raimundet (Sant Llorenç d’Hortons) and the grey limestone from the Miocene formation in Costa Blanca (Castellbisbal). The first three were used for the construction of the bridge itself and the last was used not only to cut some ashlars of the honorific arch, but also to make the lime used for the mortar.