Aims & Objectives: Housing choice of people becomes part of lifestyle choice. The gated communities offer to people a new form of housing, lifestyle and expectations in the big cities in the recent years. The aim of this paper is to discuss the change in the phenomenon of gated communities in Istanbul and their impact on the city. The paper will consist of three sections. In the first one, the concept of “Gated Community” will be introduced and its situation in the world and in Istanbul will be explored. In the second part, the differentiation between the Gated Communities /settlements in Istanbul during Eighties and Nineties will be explained. Their situation in the city today and the change process during 20 years the condition they generated will be examined. In the last (three) part, change in the gated community with their site and house plans and number of houses and their population, their social and physical properties will be examined to discover how they have changed during in the new millennium. With this aim in mind, literature review and observation will be the tools of methodology. They will support the physical and social characteristics of settlements. Context & background literature: The “gated community” concept has originated in the USA and gated communities have been built all over the world including Europe. These settlements have caused spatial and social segregation in the cities where they exist and thus degenerate the heterogeneous structure of the society. Having been specifically located outside the city, these gated communities are not accessible to citizens living elsewhere and therefore they create “new castles” in the city, disturb the social integrity and cause alienation among the people who live in the city.Method of inquiry or argument: The paper will consist of three sections. In the first one, the concept of “Gated Community” will be introduced and its situation in the world and in Istanbul will be explored. In the second part, the differentiation between the Gated Communities /settlements in Istanbul during Eighties and Nineties will be explained. Their situation in the city today and the change process during 20 years the condition they generated will be examined. In the last (three) part, change in the gated community with their site and house plans and number of houses and their population, their social and physical properties will be examined to discover how they have changed during in the new millennium. With this aim in mind, literature review and observation will be the tools of methodology. They will support the physical and social characteristics of settlements. Findings & Conclusions: In Istanbul, “gated settlements” have emerged in the 80’s for the first time as “housing blocks” which are closed to outside by surrounding boundary wall of the site. The first examples in the city have been located close the city centre and were constituted out of 4-6 storey houses which have designed in international style. In the 1990’s, these settlements were moved to outside the city to be located in the forest areas with 2-3 storey villas which have built in post-modern style in a garden (Pulat Gokmen and Ozsoy, 2002). In parallel to the change in the settlement and houses, the user profile has also changed. In the 2000’s these settlements transformed to apartments because of increased demands.