The paper attemps a sistematical analysis of the concept of quality of life. The author argues that due to the lack of a clearly defined theoretical, historical and spatial context when using the concept, its current meaning is ambiguous. The drawbacks of a poorly defined theoretical framework are evident in the difficulties encountered in identifying the variables that define a desired level of quality of life and is building up suitable indicators for measuring it. A solution to this problem requires the clasification of the development theory used to identify these variables. As a contribution in this direction the paper discusses the implicit concepts of quality of life that exists in the "welfare state" and the "ecodevelopment" theories of development. Concerning the welfare state, the author argues that the problem of quality of life is conceptualized solely as environmental goals attainable through taxation, regulation and income redistribution. In the ecodevelopment theory, the problem of quality of life is conceived as part of the central goals of a new society that veers away from the values and technology of the super industrialized society. The author puts forward a concept of quality of life based a dynamic outlock of the environment which is historically and spatially defined, thus taking into consideration not only normative aspects of the problem but also the time-space constraints affecting the process of transforming the existing environment into the desired one.