Abstract: The Yalvaç-Yarıkkaya Neogene basin is located within the Isparta-angle which is known as common regionalstructure of Southwestern Anatolia. The pre-Neogene rock units around of the basin consist generally of meta-Sediments, carbonate rocks and ophiolite complex ranging in age from Ordovician to Cretaceous. The Neogene alluvial and lacustrine depositsoccurring in Yalvaç-Yarıkkaya basin are divided in ascending order; Bağkonak, Madenli, Yarıkkaya, Göksöğüt and Kırkbaş Formations. The total thickness of the Neogene sedimentary sequence of these basin is about 800 m.The Bağkonak Formation is composed of coarse-grained and poor-sorted conglomerates and mudstone intercalations, whichindicate an alluvial-fan origin. The maximum thickness of this unit is approximately 250 m. The Bağkonak Formation rests unconformably on the pre-Neogene basement rocks and letarally interfinger with Yarıkkaya Formation toward to the center partsof basin.The Madenli Formation consists of cross-bedded sandstones, channelfill conglomerates, and above in the section, mudstoneand non-economic lignite seams which are characterized the fluvial environment. The clastic sediments of the Madenli formationare transitional laterally and vertically with the underlying Yarıkkaya Formation toward to the northern part of basin. The Madenliformation have 250 m total thickness and rests unconformably on the ophiolitic basement rocks in the southern region of basin.The Yarıkkaya Formation comosed of an. alternation of calcerous shale, clayey, limestone, marly and mudstone, which areindicate the lacustrine environment. The total thickness of the unit is 200 m at the type locality, and grades laterally in Bağkonak and Madenli formations to the northern and southern margin parts of basin.The Göksöğüt Formation consists from bottom to top of coarse conglomerate and porous lacustrine limestone. These unitoverlies conformably on the Yarıkkaya Formation. The total thickness of the Göksöğüt Formation increases to the southernpart of basin and exceeds 150 m.The Kırkbaş formation consist mainly of reddish and poor-sorted conglomerate and mudstone intercalations which appear tobe alluvial-fan origin. These unit is wide-spread in the northern part of basin and overlies unconformably on the all old units.The Yalvaç-Yarıkkaya basin is limited by the normal faults and pre-Neogene hihg mountain belts, are resemble to a triangular shape close-basin. In the basin the lateral lithofacies changes of the sediments and geometric features and distribution of thedepositional environments, indicate the Yalvaç-Yarıkkaya Neogene basin have a typical inter-mountain basin character.