Deleuze in his book on Foucault defines government as the power to affect in all its aspects. The article follows Deleuze’s reading of Foucault in order to clarify this definition. This concept of government opens a new perspective for political theory because it allows to see that governmental actions are operated not only by the State or big institutions, but also by social forces and actors. In order to understand what it means “power to affectµ in this contest, we will reconstruct Deleuze’s relation with the molecular ontology of Gabriel Tarde. Moreover, we will analyze the notion of institution that is crucial to explain the efficacy of government’s affections. This will give us the opportunity to show the breaking point between Deleuze’s micropolitics and Foucault microphysics of power. Foucault understands institutions only as limiting practices that normalize the social; on the contrary, Deleuze discovers the positive and productive character of institutions: they are able to satisfy desire and imagine new types of social assemblages.