This research provides empirical evidence on behavior, daily activities, use of space of residents living in low-cost housing in Jakarta. This study is focused on the contemporary housing units’ issue which were designed with little regard for users’ behaviour activities and which, by neglecting some of their fundamental needs (Heimsath 1977) and further leads to a range of both residents’ positive and negative perceptions toward their space and conducting a coping behaviours. The primary data, collected through semi-structured interviews with 21-sqm unit residents of low-cost housing in Jakarta, were analysed and interpreted by qualitative-quantitative methods using the Statistical Package for Social Science (SPSS) and results were further presented in descriptive form. This study revealed that the design strategies for the 21-sqm units inadequately meet the residents needs of daily activities and spatial use which was proven from residents’ negative perceptions of space and the rooms’ functions which is being utilized inappropriately and ineffective ways. The residents were enforced to adopt various coping-strategies and modes of spatial-adjustment to compensate for both physical and behavioural limitations of their living space and extended areas within housing-complex. The implications of findings suggest that architects should develop design ideas based on a more profound knowledge of potential users’ behaviour and daily activities, particularly in designing lowcost housing in which the users are mostly not involved in the design process.