More than any other country in the "Maghreb" - or even more, in Africa - Algeria is marked by the intense and rapid urban development which derives from the impacts of the huge rural migrant and the sharp increase of the demography. Many urban problems have emerged from this situation and are still far away from resolution and before any of them, is the one of "habitat". Many solutions have been envisaged for housing people during the last twenty five years, but almost non of them seems to be satisfactory. The new structural and physical aspects of housing, especially in cities have left many socio-cultural factors behind and the results are that people do not want to live in this urban environment. In addition to that, there is no continuity with tradition in such environment, and the climatic considerations are not taken into account. Thus, a new form of urban habitat has to be developed in relation to tradition , climate, and to socio-cultural component of the Algerian society. There has already been much research about the Algerian housing in many different ways, such as in planning , sociology, and in architecture, which refer at some point to an aspect of the present situation. The range of material is therefore very wide, but much of this deals with a particular field of comment, such as building techniques, climate and thermal comfort, social experiences and planning policies. The aim of this thesis is to establish a suitable physical expression for the urban habitat developments envisaged in Algeria in the immediate future. In order to produce a comprehensive environment, this expression will recognise the Algerian cultural, as well as economical, sociological, and physical context, and will seek to determine appropriate structural, environmental, and cultural criteria. I will to discuss the problem of the Algerian housing from an urban design point of view. The method envisaged is to examine traditional and contemporary urban layouts, in addition to analysing their building forms. Broadly speaking, the thesis is divided into three parts. Part one deals with the status of the existing problem of housing and is subdivided into two chapters. In chapter 1, a general description of the present Algerian habitat is stated with some particular emphasis on the new attitudes towards modernity in terms of housing. In chapter 2, however, the nature of the state's response is revealed with particular interest on the last experiences and the resent trend. This chapter will be referring to the zoning policy and the prefabricated building process of modern housing, then I will describe some aspects of the real problem that follows and how people respond to it. This should lead us to a more accurate picture of the housing crisis in Algeria. Part two is the core of this thesis and it deals with the analysis . This part is subdivided into three chapters and will examine two different types of environments determined by the traditional and the contemporary urban forms, then it will compare their respective building forms, i.e. the cluster unit and the slab unit. Chapter 1 will analyse the traditional urban form and its environment and look at the principles generating such a pattern. The pattern selected in this study represents the traditional urban settlement of Algiers: the Casbah. In chapter 2, similar analysis will be performed on the contemporary urban form, I will also look at the principles behind such a pattern. However, the pattem representing this contemporary urban form is not a real existing settlement but a typical master plan (Mendes's urban housing model) that symbolises not only most contemporary housing that prevailed during the last two decades but also the latest trend in terms of urban habitat which is strongly favoured by the present policy makers. In chapter 3, in order to do a thorough comparison of both the cluster unit and the slab unit which are generating the two district urban forms. I will first set 10 criteria according to what is found fundamental in determining both traditional and contemporary environments. Second, I will compare both units according to each criterion. Part three is the last stage, and is mainly divided into two chapters. Chapter 1 will be looking at the two selected urban forms, the Casbah and the Mendes's model it will then aim to establish a middle ground of acceptable habitat by adjusting each model against critical criteria. This process will examine the possibilities of upgrading both models which should lead us to a more appropriate housing layouts. Chapter 2 will take the form of a general conclusion that should determine the main important concepts behind the physical expression of an appropriate habitat for future development in Algeria and what measures can be taken by a governmental department in order to select appropriate proposals for future habitat that it would be worth the government investing in.