This paper offers a statistical analysis of the importance of urban green areas as critical constituents of sustainability policy of cities. Special attention is given to the background conditions and factors that are responsible for effective urban green space planning. Based on a systematic extensive database on relevant attributes of urban green in 23 European cities, our study aims to assess performance indicators for the effective provision and maintenance of green spaces in these cities. By using multivariate statistical analyses, we provide an operational framework for quantitative comparative study of such green spaces. Based on this comparative analysis, we derive transferable policy lessons on sustainable urban green spaces, in particular regarding the need for effective institutional support systems and the need for tailor-made flanking financial mechanisms for green space policy. Copyright © 2012 Inderscience Enterprises Ltd.