Abstract: The formations of Campanian-Lutetian age are exposed in the region of Haymana, SW of Ankara. These formationsof about 5000 m thickness are represented lithologically by conglomerates, sandstones, shales, marls and a veriety of limestones.The formations named by Yüksel (1970) as Haymana, Kavak, Çaldağ, Kadıköy, Gedik, Karahoca and Çayraz were sampled, and107 Nannoplankton species have been distinguished in the samples collected. By means of these Nannoplankton forms that thefollowing biozones have been defined in the area studied: Tetralithus gothicus, Tetralithus trifidus, Arkhangelskiella cymbiformis,Lithraphidites quadratus, Cruciplaculithus tenuis, Chiasmolithus danicus, Ellipsolithus macellus, Fasciculithus tympaniformis,Heliolithus kleinpelli, Discoaster gemmeus, Discoaster multiradiatus, Marthasterites contortus, Discoaster binodosus, Marthasteritestribrachiatus, Discoaster lodoensis, Discoaster sublodoensis. These zones of the research area were correlated with the other regions,and their compatiblity with the planktonic Foraminifera zones described there were proved. Moreover, an environmental interpretation based on the Nannoplankton species is also provided here.