Kayabaşı is a neighbourhood in the municipality and district of Başakşehir, Istanbul Province, Turkey.

[2] It was formerly known as Ayayorgi (from Greek: Άγιος Γεώργιος, "St. George") and Azatlı until the Greco-Turkish population exchange of 1923.

Kayabaşı was a district of Bakırköy until 1987 then it was a quarter of Küçükçekmece where was a part of the Çatalca kaza until 1908.

The cave is an important fossil site which has been researched by archeologists, paleontologists, geoarchaeologists and biospeleologists.

Due to necessity of water for producing gunpowder Şamlar Bendi was built in Mahmut II's reign in 1826–1828.

Muslim inhabitants firstly settled in Yeşilköy in Istanbul but it is not suitable for animal husbandry especially goat raising.

Then they settled in Kayabaşı and Mahmutşevketpaşa in Istanbul, and also others Halitpaşa in Manisa, Kadıköy in Keşan, Yağcılar in Akhisar and some villages of Orhangazi, and İznik in Bursa, hence Orthodox Christian inhabitants in Kayabaşı most of them went to Kayalar(Greek: Πτολεμαΐδα, Ptolemaïda) in Greece from Turkey.