Abstract: The indoor air quality represents one of the factors conditioning housing quality in urban residential spaces. The paper analyses the spatial and temporal distribution of parameters defining the indoor air quality from representative housings in Bucharest, correlated with their influence factors. The characterisation of permanent, seasonal and circumstantial influence factors was realised using the US EPA (1991) and WHO (2006) methodologies. Between November 2008 and February 2010 there were applied questionnaires for appreciating the dimension of influence factors inside and outside the housings. In the same time, for determining the values of representative indicators analysing the indoor air quality, measurements were realised in selected housings. From analysing the obtained results, it can be stated that in the indoor habitat of most residential spaces from Bucharest, the quality of air is unsatisfactory, values of human comfort recommended by international legislation being exceeded at indicators such as: volatile organic compounds, carbon dioxide or particulate matter. The building’s ventilation systems are mostly dismantled or not functioning, and as a result the thermal isolation of buildings only aggravates these problems as it isn’t compensated with an improvement of the ventilation systems. The significant expansion of areas affected by Sick Building Syndrome, which are economically, ecologically and/or sanitary inefficient, in the framework of recent environmental changes, it requires an integrated approach of problems concerning the air quality management in Bucharest residential spaces.