Hasandag and Erciyes stratovolcanoes, which produced both calc-alkaline and alkaline eruptive products, are the two important volcanic complexes in Central Anatolia. There are three geochemical evolution stages in the history of the Hasandag strato volcanic complex: (1) Kecikalesi tholeiitic, (2) Hasandag calc-alkaline and (3) Hasandag alkaline. Volcanologic and petrologic characteristics of the Hasandag and Erciyes calc-alkaline series show that water played an important role on the genesis of these rocks. These rocks are phenocryst-rich with vesicular texture, and contain hydrous mineral phases. The approximate pressure and temperature estimates obtained from the mineral chemistry studies of the Hasandag strato volcanic complex indicate crystallization temperature of 1100 degrees C with 2.5-3.4 kbar pressure interval for the first stage of Kecikalesi tholeiitic volcanism, and about 850 degrees C temperatures with 4.3-9.6 kbar pressure intervals for the second stage of Hasandag calc-alkaline volcanism.