Aydın Eski Hamam is a typical example of Ottoman period bath buildings. It had been built during 15th-16th centuries, and subjected to extensive interventions by present. The building was registered in 2001, and excavation, cleaning and measured surveys were carried out in 2016-2017. The aim of this study is to determine the characteristics of the horasan and lime plasters of Eski Hamam. Within this purpose, horasan and lime plasters, joint mortars and building bricks were collected from the bath. Basic physical properties, raw material compositions, microstructural and hydraulic properties of plasters, mineralogical and chemical compositions of binders and aggregates, and pozzolanic activities of aggregates were determined by standard test methods, XRD and SEM-EDS analyses in order to shed light on the restoration implementations. The results revealed that all the studied samples were of low density and high porosity. Physical, chemical and microstructural properties of plasters did not differ according to the space, level and layer they had been used. Horasan plasters had been prepared by using pure lime and brick aggregates. Lime plasters used on the upper levels had been produced by using pure lime and small amount of fine sand. Horasan plasters were hydraulic due to the use of pozzolanic aggregates. Brick aggregates had been manufactured by using raw material sources containing high amounts of clay minerals, and fired at low temperatures. Lime plasters and mortars had hydraulic properties due to the use of pozzolanic natural aggregates.