A thorough investigation of calcareous nannofossils from the Jaddala Formation in Western Iraq in (Kh1) well has been undertaken. Twenty four species of calcareous nannofossils are reported in eleven genera belonging to eight families as followings Helicosphaeraceae family by the genus Helicosphaera (H. ampliaperta, H. compacta , H. lophota, H. salebrosa, H. seminulum), Zygodiscaceae family by the genus Nannotetrina (N. cf. cristata), Rhabdosphaeraceae family by the genus Blackites( Blackites sp.), Coccolithaceae family by the genus Coccolithus (C. miopelagicus, C. pelagicus, C. staurion) and the genus Erocsonia (E. formosa, Erocsonia sp.) Noelaerhabdaceae family by the genus Cyclicargolithus(Cy. Abisectus), the genus Dictyococcites (D. bisectus) and the genus Reticulofenestra( R. dictyoda and R. umbilicus), Prinsiaceae family by the genus Toweius (T. occultatus and T. pertusus), Discoasteraceae family by the genus Discoaster (D. bifax, D. deflandrei , D. cf. nodifer, D. saipanensis) and the Sphenolithaceae family by the genus Sphenolithus (S. obtusus and S. pseudoradians). It is a three biostratigraphic zone that has been observed, and its age has been estimated as middle Eocene for the Jaddala Formation. Coccolithus staurion Partial range biozone (CP13c); Discoaster bifax Partial range biozone (CP14a) and Discoaster saipanensis total range biozone (CP14b). Therefore, we suggested the middle Eocene (Lutetian to Bartonian)