This thesis addresses the role of the birth complex in Friedrich Nietzsche’s philosophy and in Richard Wagner’s operas. I see the birth complex as characterised by a dialectical relation between flesh and light, which is itself polarised by the tension between desire and anxiety. A structural determinant of the human relation to the world, this complex in my argument is of special importance for understanding the roles given to and assumed by women. Wagner gave the birth complex its first comprehensive elaboration through his operas. This, I contend, is the aspect of Wagner’s work that Nietzsche in his writings particularly reacted to through the ambivalent fascination it awakened in him. I argue that, even after Nietzsche’s break from Wagner, the birth complex remains central in his philosophy. The primary reference I build on here is Otto Rank’s theory of birth trauma, as set out in Das Trauma der Geburt (1924). To me, Rank’s theorisation of the trauma of birth is a translation into psychoanalytic language of Nietzsche’s philosophy, which itself arose with a translation into philosophical language of Wagner’s operas. In this thesis I build especially on Rank’s formulation of the tension between desire and anxiety and on his suggestions concerning the causes of the undoing of women. However, Rank did not take into account what I contend is a key aspect of both Nietzsche’s and Wagner’s work: the role of light in its dialectical relation with the flesh. By flesh I mean the interiority of the mother’s body and, by extension, the human body insofar as it is conceived through its relation to the maternal body. In the first main section of my PhD, I propose a theoretical understanding of the birth complex through an analysis of Nietzsche’s philosophy. I start with his writings pro and contra Wagner, showing that what Nietzsche primarily sees in Wagner’s operas is the birth complex. I then go on to argue that Nietzsche’s philosophy of life and of creativity is an exploration of the ways in which birth could be overcome. The second main section of my PhD is dedicated to Wagner, with largely text-based readings of three operas. I first discuss the extent to which death in Der fliegende Holländer and in the Freudian conception of the death drive is a mask for birth. I then tackle Tristan und Isolde and its famous celebration of night and death, in order to investigate whether love can be reduced to the birth complex. The last chapter of this section presents a close analysis of Das Rheingold and especially of its first scene and of Wagner’s indications on lighting. In a third and shorter section, I show that Hugo von Hofmannsthal’s and Richard Strauss’s Elektra pursued and reviewed this fundamental preoccupation of Nietzsche’s and Wagner’s work in proposing a further formulation of the birth complex that incorporates the scene of matricide. Finally, as a coda to the thesis, I explore the extent to which the uses of stage lighting pioneered by Adolphe Appia have been coming to terms with the birth complex.