This report presents the results of X-ray fluorescence (XRF) analyses conducted on fourteen bulk rock samples collected from several survey regions in the southeastern part of the Regional Unit of Grevena, within the Mesohellenic Trough. The investigated materials represent a range of sedimentary lithologies, including sandstone, marly sandstone, conglomeratic sandstone and conglomerate, originating from the Kipourio (Eptachori equivalent), Basal, Krania, Pentalofos and Tsotyli molassic formations. In addition, one sample of serpentinized harzburgite derived from the Mesozoic ophiolitic basement was analyzed to provide a geochemical reference for ultramafic source material potentially contributing detritus to the basin deposits. The samples were collected during field surveys held under the PilotSTRATEGY research project and the analyses provided quantitative determinations of major, minor and selected trace elements in order to characterize the bulk geochemical composition of the studied lithologies. The results contribute to the geochemical characterization of the molassic sedimentary units of the Mesohellenic Trough and provide additional constraints on the influence of siliciclastic, carbonate and ophiolitic source materials within the basin.