Abstract: 22 represantative samples of volcanic rocks taken from 16 formations (Eocene-Recent) from Ayvalık,Edremit, Dikili, Bergama, Soma, Bigadiç, Kepsut, Sındırgı, Gördes, Demirci, Kula, Denizli and Söke districts ofWestern Anatolia were analysed for major, trace and rare earth elements for Sr isotopic ratios and radiometricallydated by (K/Ar) method. Rocks of rhyolitic to basaltic composition yielded calc alkaline affinities with the exception of some alkaline basaltic rocks through application to various diagrams.The samples are rich in Ba, La, Pb, Mo, As, Rb, Sn, Sr, Th and U; implying an intraplate origin and anatecticmelting of the continental crust. It seems that the youngest phase of Kula basalts are possibly the only rocksoriginated from the mantle according to evaluation of normalized trace and rare earth element contents. Othersamples suggest partial melting of the Continental crust with indications of contaminations supported by Sr isotopic ratios of 0,7030-0,7096. Alibey Volcanics (31,4±0,4 m.y) and the youngest phase of Kula basalts (25000 ±6000y) respectively correspond to the oldest and youngest Tertiary events.