PurposeTurkey has been rapidly urbanizing since the 1950s. In quantitative and qualitative meanings, the problem of housing is one of the most important subjects on Turkey’s agenda. Increasing population, rapid cultural and economic transition and the dynamics of in-migration, changes in social life, consumption patterns and value systems have made a significant impact on housing demand and supply. If we try to realize a general analytical outlook to define the basic formal and informal categories that reflect specific values pertaining to housing typology of the twentieth century, it would be possible to make a classification under the following sub-titles: formal housing-row houses, separate houses, apartment blocks, social housing, mass-housing, luxury housing including gated communities; informal housing – squatter settlements/gecekondus, slums; inbetween –apartkondus, unpermitted constructions/building extensions. The paper aims to discuss these issues.Design/methodology/approachIstanbul has been experiencing these various dynamics of planned and unplanned housing settlements in a very radical way, since the 1950s. Changing typology is examined systematically under certain periods up to now. In confronting housing needs under rapid urbanization, “types of housing supply channels” appeared and as a result, urban texture has been changing by periods. In this paper, in order to understand each of these categories and the conditions under which they have been generated, an analysis will be realized to understand the urban housing concept of Istanbul within the twentieth century urban environment.FindingsThe factors playing a role in the evolution of twentieth century dwelling forms on Istanbul will be defined, and the physical/architectural, locational, neighborhood characteristics, as well as their user profile will be examined.Originality/valueThis study is expected to contribute to the further understanding of the urban housing stock and the future trends in housing typology.