Most safety net programs in low and middle-income countries have hitherto been conceived for rural areas. Yet as the global urban population increases and poverty urbanizes, it becomes of utmost importance to understand how to make safety nets work in urban settings. This paper discusses the process of urbanization, the peculiar features of urban poverty, and emerging experiences with urban safety net programs in dozens of countries. It does so by reviewing multidisciplinary literature, examining household survey data, and presenting a compilation of case studies from a 'first generation' of programs. The paper finds that urban areas pose fundamentally different sets of opportunities and challenges for social protection, and that safety net programs are at the very beginning of a process of urban adaptation. The mixed-performance and preliminary nature of the experiences suggest putting a premium on learning and evidence-generation. This might include revisiting some key design choices and better connecting safety nets to spatial, economic and social services agendas compelling to urban areas.