It is well-documented that urban waste contributes to the economy by creating livelihoods. Less is known, however, about the role of urban waste in producing human–animal ecologies involving livestock and wild birds. Here, four aspects of human–animal relationships in two urban subsystems involving waste as raw material for both stall-fed livestock (focusing on cows) and foragers (focusing on kites) are discussed. These are the roles of waste as feed; complex spatial relationships between animals, humans and their wastes; high densities of animals and humans leading to conflict over waste; and emerging threats of diseases spilling across social and physical barriers between animals and humans mediated by waste, with implications for the health of urbanised living beings.