The study aims at identifying the environmental adaptation of slum dwellers with their resettlement in new cities and in development housing projects. Identifying as well if the state's plans consider the social، environmental, and economic dimensions of people during moving to new societies and which types of resettlement are more appropriate for the population and to achieve environmental adaptation، what measures the population may take to try to adapt to the new home; in addition to impact of this adaptation on their affiliation and popular as well as societal participation. In order to reach the study results، Monshaat Nasser district has been selected as one of the slums and Suzan Mubarak residences as one of the development projects areas. The study relied on the descriptive method using the social survey to describe and diagnose the study populations، and compare them to identify similarities and differences and compare them regarding the environmental and social characteristics، adaptation level، and what is reflected on the forms of belonging. The researcher uses a number of tools such as a questionnaire، scales، the observation، and statistics. The most important results of the study are as follows: There is a strong direct positive correlation between environmental adaptation and affiliation; the strongest is the environmental adaptation، the strongest is affiliation، in favor of the residents of the Monshaat Nasser area. There is a positive correlation between environmental adaptation variables (habitat، spatial environment، neighborhood environment) and affiliation which most related to affiliation are adaptation to the living environment، then to the housing environment and to space. There are clear indications of the divergence of environmental adaptation، the inhabitants of Suzan Mubarak housing are the most adapted to their environments. Housing of development projects has proved to be the optimal for adaptation. Recommendations: The Fund for the Development of Slums and the New Urban Communities Authority should consider the environmental dimensions of the resettled population by developing comprehensive planning stemming from their needs and working on adapting them to new environments.