As the “urban crisis” hit major American cities in the sixties, the nascent field of urban economics was still struggling with its identity. In the previous decade, Ressource for the Future had funded and coordinated economists' efforts to explain metropolitan growth (size and distribution of activities and income, rents, transportation) with a variety of tools, ranging from input-output analysis to consumer choice theory. Yet, the relationship to neighboring subfields (regional economics), sciences (architecture and engineering) and broader interdisciplinary ventures (urban studies and city planning) was not stabilized. In the wake of the 1963-1965 riots, new questions and fundings flowed from govermental agencies and foundations, with the aim of understanding and curing crime, racial segregation, poverty, congestion and pollution, and replacing ghettos with “model cities.” This papers shows how such social demand for new visions and policies impacted the formation of urban economists' identity. It described economists' diverging views of the relevant subjects, methods and boudaries of urban economics and the right level of participation to political decisions and policy making. Most visible on the public scene were those economists loosely related with the Chicago school of economics. They borrowed both from the imperialistic application of choice theory and the Chicago applied tradition in agriculture and econometrics, not only to formulate practial solutions to the new diseases of American society, but also to frame a political discourse. Such venture was challenged, in scope and content, by economists from the East coast, albeit with various purposes and styles. At Harvard, economists from various disciplinary backgrounds attempted to shape interdisciplinary and integrative plans to tranform the Boston Area and to create institutions and curricula for their discipline. The MIT setting exhibited a division between those researchers willing to use insights from other subdisciplines (labor, development and growth economics) to meet specific practical demands from reformers, and those who worked on a general framework based on general equilibrium models and insisted to stay aloof from political and policy debates.