This thesis explains the relationship between ressentiment, nihilism and fascism, using Nietzsche s philosophy and Gilles Deleuze s interpretation of it. It begins with an overview of the history of the concept of fascism, using ideas such as the suicidal state and realised nihilism. It then shows the current consequences of far-right political movements. The next chapter deals with the original diatribe on nihilism, which permeated German idealism, and its importance in 19th century Russian literature. Together with Nietzsche, it shows the relationship between nihilism and the death of God and the Übermensch. Within the author s work, understandings of nihilism are mapped, using commentators such as Deleuze himself. Based on Deleuze s reading of Nietzsche s nihilism, the thesis interprets the posthumously published Lenzer Heide, a reference in studies on nihilism, showing its reverberations in organised violent movements. In the last part, the thesis creates a certain history of ressentiment, going through the ancient Greeks and arriving at Montaigne. It shows how affection first appeared in Nietzsche: in a discussion on Justice, in opposition to Dühring. The investigation moves on to Dostoevsky and the Underground Man, to show the Russian writer s influence on Nietzsche. Then, using the Genealogy of Morals, we discuss the possibilities for the reactive forces of ressentiment to appear and how active forgetting can function as a kind of antidote. It also shows how ressentiment can, on the other hand, be the source of political insurgency movements and how there are almost antagonistic ways of understanding ressentiment. As a way of exemplifying the process, this work uses Machado de Assis and the notion of favour. Finally, it shows other related reactive affections, such as bad conscience and the ascetic ideal, in order to equate these affections, with the help of Adorno and Horkheimer, with the notion of fascism.