Contemporary provision of open spaces within cities rests largely on professional assumptions about its significance in the lives of residents. This paper presents results from the Greenwich Open Space Project which used qualitative research with four, in-depth discussion groups to determine the design of a questionnaire survey of households in the borough. The research shows that the most highly valued open spaces are those which enhance the positive qualities of urban life : variety of opportunities and physical settings; sociability and cultural diversity. The findings lend some support to the approach of the urban conservation movement but present a fundamental challenge to the open-space hierarchy embodied in the Greater London Development Plan. The Project identifies a great need for diversity of both natural settings and social facilities within local areas and highlights the potential of urban green space to improve the quality of life of all citizens.