In this brief article I expound some uses that Hobbes gave to the concept of multitude. Firstly, I explain the distinction between "people" and "multitude", the confusion of which was regarded in De Cive as a cause of sedition. The plural and disunited character of the multitude is highlighted, in comparison with the unity that constitutes the people. Secondly, I show that Hobbes, beyond the cited distinction, makes a relevant use in Leviathan of the principle of representation, in order to show the way in which multitude becomes State. Finally, I highlight the two-fold use given by the author to such concept: on the one hand, by attributing a theoretical role to it, which should allow thinking of the rational construction of the State; on the other, by showing the historical reality of multitude, turned into a source of madness and sedition.