The excavation of Ancient Ahlat City has started 45 years ago by Prof.Dr. Prof.Dr. Haluk Karamağaralı, and resumed under the chairmanship of Assoc. Prof. Dr. Nakıs Karamağaralı from 2005 to 2010. The excavations of old hamam were finalized at the end of the excavation season of 2010. The bath has two parts which are specialized for women and men. Both parts has a cross shaped plan and has 2500 m2 area in total. The bath is a unique building found in Anatolia with four the iwans and eight halvets symmetrically designed. The excavation process in general, the restitution of the hamam in detail is presented in this article. The restitution study is realized on the basis of the existing parts and the traces of the building that are found at the site, the excavation reports held by Prof.Dr. Haluk Karamağaralı, and the comparative studies on bath literature.