Abstract: Results of the stratigraphic investigations on the magmatic and sedimentary rocks cropping out between Edremit and Korucu (Balıkesir) in Western Turkey have been presented and the origin of volcanic rocks o£the region have been discussed- The oldest volcanic sequence of the area is represented by the Bağburun formationwhich is probably of Paleocene-Eocene age. Magmatic activity continues with the Eybek and Kozak plutons whichare covered by the Hallaçlar volcanics of Upper Oligocene-Lower Miocene age and with the Dedetepe formation(Lower Miocene). This is in turn succeeded by the Ballıca formation (Middle Miocene), and Soma formation (MiddleMiocene-Lower Pliocene). The continental Neogene sequence ends with the Rahmanlar agglomerate of possible LowerPliocene age- From the point of view of regional geotectonic evolution and petrochemical properties, the Bağburunformation is derived from a subduction zone and may be assumed as an arc volcanism. The younger volcanicswhich are represented by the Hallaçlar and Dedetepe formations have been derived from the anatexis of thecontinental crust and they may be grouped as intracratonic volcanics. All these three volcanic phases show calc-alkaline characteristics.