Rapid urbanisation which is a characteristic of most developing countries, has led to the importation of readily available solutions and to an overgeneralisation of human needs. The main objective of this study is to relate design to man's social and cultural needs. First, the study demonstrates the relationship between cultural and social variables that influence house form and settlement patterns. This is followed by a comparative case study analysis of existing house-settlement systems in two residential areas; one a modern government built scheme, the other a traditional development, both in the M'Zab, in Southern Algeria. The main assumption was that traditional houses and settlements were culturally more responsive than their modern equivalents. However, results refuted this assumption and indicated that social change affected many of people's values and attitudes towards housing. This indicates that neither international modernism, in housing provision, nor an attempt to slavishly copy past indigenous solutions are likely to be successful. Through studying human-environmental behaviour and using multiple-methods strategies, it is possible to bridge the gap between design and social research. A reorientation of the educational system would help towards a better communication not only between different professional practices and disciplines, but also involving the lay people. Finally, this study suggests that designing for potential adaptability a characteristic of traditional design, reflects culture, and would not only accommodate change, but would also involve active participation by people and therefore raise the level of responsibilty and satisfaction. The research combined evidence from documentary sources and field surveys. A multiple-method strategy was adopted to compare the two settlement systems of the case study. This included direct observation, interviews and trade-off games. The interview survey included three groups of people: the users, the local planning authorities and the building contractors. By stressing the socio-cultural variables, this study does not deny the role of other variables. On the contrary, the author accepts that design activities should aim towards maintaining a balance between environmental factors and financial constraints. It is, however, argued that human needs must be given at least the same degree of importance, if workable solutions to the problem of rapid urbanisation are to be found.