Music’s role in Decadent art and debates about Decadence was varied, almost ubiquitous and at times contradictory: it cannot be confined to particular composers, to formal matters, to metaphor or even to musically informed usage. This chapter makes this diversity (some would say messiness) a principle of the argument, embracing the breadth of meanings attached both to Decadence and to music’s role in it. Decadence is here understood broadly, acknowledging its currency in and across disciplines and discourses including (most pertinently to this chapter, but not limited to) the mental sciences, art history, literary criticism, aesthetics and sexology. Recognizing music’s importance to Decadent art and its reception involves acknowledging music’s intersection with discourses from evolutionary theory to sexology to mysticism to nationalism and consumerism. This chapter begins by briefly surveying musical allusions in Decadent writing and considering music’s importance to Decadent style and formal innovations. It turns then to music’s role in the cultural and critical discourse about Decadence.