The language of criminologists provides insights for studying the interconnection between prison reform and contending discourses about social questions in two countries experiencing rapid integration into the world market. Argentina and Brazil both faced new social problems associated with the emergence of a predominantly immigrant, urban and mobile working class, but responded differently to the challenges of criminality. While Brazilian criminologists found race useful for explaining the country's economic backwardness and the lack of integration of the peasant majorities into the project of progress, Argentine criminologists emphasized the influence of the social environment of the city and the psychopathological traits of individuals to explicate criminal behavior. Endowed with the new powers of observation gained from the penitentiary-as-clinic, criminologists interpreted the social question and evaluated the consequences of export-led growth on social control. As a result, a similar type of knowledge served to construct two different criminalities and two distinct social questions. Notes