In his book The Conservation of European Cities, Donald Appleyard stated that, "The old city exemplifies the human scale, individuality, care and craftsmanship, richness and diversity that are lacking in the modern plastic, machine-made city with its repetitive components and large scale projects." However, many historic cities are in danger of becoming plastic because of tourism development despite the distinctive qualities they once had. Recent layers are not valued, faux elements are used to keep historic identity of built fabric, or diversity gets lost by replicating a selected type of architectural form. This thesis looks both into intended and market driven changes before and after "tourism explosion" in three towns in western Turkey, and tries to understand what happened to these "old" qualities in the course of change so that reasons behind homogenized historic settlements can be revealed and proper planning and management can protect against the homogenization process.