We assessed the biodiversity in urban green spaces in two study areas in Sweden, one in Malmö (Lorensborg and Bellevuegården) and one in Södertälje (Ronna). Both areas are characterised by high-rise residential housing built in the 1950s–1970s. These types of city districts have been investigated less often regarding their biodiversity values. Here, we have developed a method for biodiversity assessment of urban green spaces that can be performed at city district scale in particular in districts with public and residential green spaces. To assess biodiversity, we chose three measures: (1) number of habitats, (2) tree and shrub species (taxa) and (3) indicators such as the estimated abundance of dead wood, floral herbal resources and management intensity. Most green space types prevalent in both study areas were included, such as parks, residential green areas and street green (but not private gardens). Twenty-seven different habitat types were recorded, with lawns, hedges and shrubs being the most common. In total, 145 tree and bush taxa were identified; the proportion of non-native taxa was 73% in Malmö and 62% in Södertälje. In both study areas, we observed a high management intensity in many green spaces, which resulted in a diminished potential as wildlife habitats. Planning programmes were ongoing in both study areas. In Malmö, there are densification projects, which underline the risk of losing green infrastructure due to exploitation in these types of city districts. Among biodiversity assessment methods, our methodology is of medium intensity and combines direct measures with indicators for biodiversity.