This paper focuses on a distinction between two kinds of theories about the role of institutions in cosmopolitan justice. Some philosophers claim that principles of egalitarian justice apply to institutional schemes only, and do not apply to the actions of individuals. Others think that principles of egalitarian justice apply also to the actions of individuals. I aim to clarify this debate with a view on cosmopolitan justice by examining whether institutions can make a non-instrumental difference to what people ought to do with regard to distributive justice. I begin by outlining two positions concerning the significance of institutions in cosmopolitan justice. The first position argues that institutions enable a more effective discharging of individual preinstitutional duties, however both institutions and individual conduct are to be evaluated with the same fundamental principles. The second position aims to establish the special significance of institutions in global justice by regarding them as possible channels of collective harm. In contrast to these two strategies, I provide an argument for regarding institutions as making a non-instrumental difference to what people ought to do with regard to cosmopolitan justice. The argument purports to establish that some fundamental cosmopolitan principles of justice do not apply to individual conduct directly. It emphasizes the constitutive role of global institutions in distributive justice on the basis of the conditional character of moral duties and of the systematic nature of institutional schemes. The thesis is justified by reference to the capacity of institutions to solve coordination problems and conflicts raised by the fact of disagreement, and their capacity to determine a unique set of just distributive rules, given the essentially underdetermined character of the demands of justice.