Abstarct: In this study, petrography and geochemistry of the sandstones and shales of Padeha Formation in Khoshyeilagh section in Eastern Alborz have been used to obtain more information on their provenance. Padeha Formation in the studied section has a thickness of 341 meters and is underlain by the Late Ordovician-Silurian SoltanMeydan basalts. After field studies, 20 medium-grained sandstone samples were selected for point-counting and 8 sandstone samples and 2 shale samples were selected for geochemical analysis and 3 sandstone samples and 2 Shalein specimens were selected for mineralogical composition. baxsed on the calculated percentages of point counted data, the composition of these sandstones has been detected as quartz¬arenites, sub¬arkose and sub¬¬¬litharenites. baxsed on Q/Q+F in sandstones and geochemical properties of sandstones and shales, such as Al2O3/TiO2 ratio and TiO2 against Zr, the dominant source rock of these deposits can be considered as felsic igneous rocks. The QmFLt and QtFL diagrams show the tectonic setting of Padeha Formation sandstone as stable cratons. The geochemistry has also largely confirmed the tectonic setting of passive continental and rifted margins. Considering paleogeography of the region, tectonic uplifts and erosion of the Cadomian granitic baxsement and also the entrance of clastic materials from granitic rocks of Arabian craton can be considered as the other source rocks of the sediments of Padeha Formation.