We report on a large-scale household survey conducted in the city of Nanjing, in 2005, which forms a preliminary study for a major ESRC/DFID funded investigation into urban poverty and property rights changes in China. To capture an initial portrait of the urban poor, the Nanjing study focuses on the most essential elements of their daily lives, i.e. demographic characteristics, access to social entitlements, housing conditions, neighbourhood interactions and social networks. It is the first study to comprehensively examine the morphology of urban poverty at the city scale. Urban Hukou (urban citizen rights) households with no unemployed member are found to be better off than working rural migrants. Urban Hukou households with at least one unemployed member have a similar poverty incidence to rural migrants; the latter suffering from a series of interrelated disadvantages. There are distinct groups of urban poor, each being affected by a particular set of impoverishing factors. Poor urban-registered households are typically characterised by unfavourable personal or household characteristics, such as a large number of dependent household members and prior employment in a state owned enterprise. The impoverishment of rural migrants is largely connected with institutional discrimination such as lack of rights to social security benefits and unfavourable employment opportunities.