Throughout history, the Anatolian Peninsula, with its many fertile lands and many settlements of civilization, has seen a bridge between civilizations due to its position on commercial and military roads. Ankara, the capital, since the establishment of the Republic of Turkey; is a witness to many political, administrative and military events that have been up to date. For this reason, the city has a rich cultural heritage. Ankara Castle, which has always been in the same place since the Hittites, repaired many times during the Roman, Byzantine and Seljuk periods. It is very important that the materials used in the restoration work are compatible with the existing structure. In this; an analysis of the existing material was carried out which could shed light on the restoration work to be done on the Ankara castle.