AbstractThis paper will explore whether and how different modes of postsocialist urban transformation of inherited large housing estates (LHE) from the socialist past have influenced quantitative changes in urban green space (UGS) at the neighborhood level. The investigation will be conducted on a representative LHE neighborhood in the city of Niš, Serbia. This paper will introduce the Urban Green Transformation Index (UGTI) that combines five weighted parameters by employing the geographic information system–multicriteria decision-making (GIS–MCDM) method, which uses linear aggregation with a weighted overlay approach. This describes the impact that transformations have on UGSs for their permanency. The results from this paper indicate that the LHE redevelopment processes have caused constant pressure on the UGS throughout the postsocialist period, which has led to their regressive changes. The index presented in this paper could be used as a corrective, or mandatory, or both urban and land use planning and decision-making tool when assessing the degree of environmental and social sustainability of newly planned construction within the LHE neighborhoods.