Anaia Church, which is thought to have been in use from the Early Byzantine Period to the Late Byzantine Period, is located in Kadıkalesi, Kuşadası. Kadıkalesi is a Byzantine Period fortification that it is thought to be built to protect harbour of Anaia ancient city, which was a bishopric throughout the Byzantine Period. Today, the three aisled basilical planned church is in state of ruin and excavations are on going in the area. The building reflects architectural planning, construction technique and architectural element features from the 5th century to the 14th century, was determined as the subject of this thesis to document and develop a conservation proposal. The study began with field survey and the building was documented with drawings and photographs. Planning, constrcution technique, architectural elements and the conservation problems of the building were evaluated and finally a conservation approach was developed in accordance with the data obtained throughout the study. In the analyses, it was seen that Anaia church shows parallel planning evolution that represents the features from the Early Byzantine Period to the Late Byzantine Period. The centrally located ambo in the nave and synthronon in the apse reflect the Early Byzantine Period features. The filling walls and toppled columns revealed in the naos were evaluated as physical effects and measures of earthquakes. Stepped pilasters in the northern and southern façade walls and recessed brick technique in the northern façade wall are the features of construction technique. The majority of the observed problems in the building are related with exposure to the atmospheric conditions since the roof of the church has not survived to present. Furthermore, it was observed that the temprorary protective shelter at the east and west end of the church, is inadequate. As a result, to conserve the Anaia Church as a cultural asset, drainage in the area, protective shelter, supporting of the arches and vaults, consolidation of the walls, conservation of the floor coverings and removal of humidity from the substructure were proposed.