Based on the authors’ parallel projects of research and fieldwork in urban informal settlements in Durban and Nairobi, the article uses comparison to bring out similarities and differences between the lives of youth, popular culture, moral debate, and local politics in a South African and a Kenyan setting. The two historical trajectories of settler colonial state building, urban influx control, and segregation are contrasted, as are the contestations that accompanied decolonization and transitions to democracy. The paper debates understandings of ‘informality’ in the context of economic activity, housing, and politics, discusses the ways in which informal enterprise has come to have different weight in South Africa and Kenya, and shows the impact of different expectations of state services in the two environments. In conclusion, the authors try to assess the degree to which the developments of poor urban areas in Durban and Nairobi are converging, whether they will represent different patterns of urban integration, and to what extent the ‘interface between formality and informality’ negotiated in South Africa and Kenya are indicative of more general, global trends.