Abstract. The Rashrashiyah Formation of the Sirhan Basin in northern Saudi Arabia contains diverse assemblages planktonic foraminifera. We examined biostratigraphy, stratigraphic range and preservation upper Eocene Assemblages are well-preserved diverse, with 40 species 11 genera. All samples assigned to Priabonian Globigerinatheka semiinvoluta Highest Occurrence Zone (E14), consistent calcareo...