Abstract: In the Beypazarı, region, metamorphic rocks of the Middle Sakarya massif are intruded by a low temparatured and shallowemplaced batholite. Composition of the batholite body shows variation from granite to diorite,but the granitic rock are predominantoverall in the region. The batholitic body, generally named as the Beypazarı granite, outcrops at the south of the Kirmir stream, isprobably connected to those granites occuring around Sivrihisar; although it is unconformably overlain by Paleocene, Eocene andMiocene rock units from place to place. The homogeneous batholite has a small varience within its body and shows a sharp instrusive contacts with the surrounding metamorphic rocks, consisting of phyllite,schist and marble. Hornfelses, which range between 3 to10 m in thickness, are present along the contact zones from place to place. The batholite has xenoliths taken from wall rocks alongthe marginal parts during its emplacement. Siliceous iron formations are observed in some places wherever the batholite cuts theiron-rich met amorphics.Joint systems and fractures were formed penecontemporaneously paralel to tlie cooling of the magmatic body during the graniteemplacement. Aplite and pegmatoid dykes which vary 10cm to 6m in thickness and 10m to 350m in length, trending NE-SW and NW-SE are formed along the fracture at the later phase. Granite and granodiorite componets of the batholitic body have xenoliths *••of monzodiorite and diorite, which were formed in an earlier phase according to magmatic differantiation.Granites consist principally of quartz plagioclase, orthoclase and minor amphibole, biotit, chlorite; zircon, sphene, apatite andopaque mirerals. Felsic minerals decrease whereas mafic minerals increase towards the diotiritic parts of the body and pyroxenemineral are also observed. Plagioclase and orthoclase show sericization, wfiereas biotite show chloritization. Predominantly holocrystalHne, hypidiomorphic and less commony, myrmekitic and allotrimorphic textures are present in the granits.AFM and (NaO+K20) /SiO2 diagrams show calk-alkalen character of these rocks. Alteration and metasomatism have modifiedRb/Sr, K/Rb, and K/Na rations. The initial 87Sr/ * Sr rations, ranging between 0.706 and 0.707 indicate that the Beypazarı graniteswere formed by anatexis of older continental cruts, and are shallowly intruded to the region probably during the Upper Cretaceoustime.