This dissertation studies the cultural concept of “decadence” in Latin America during the nineteenth and twentieth century. It focuses on the reception of Cuban writer Julián del Casal (1863-1893) as an emblematic case. It approaches “decadence” in literary, sociological and historical terms, and relates its emergence (as cultural concept) to the legitimation crisis of colonialism brought about by the advent of industrial capitalism in the nineteenth century. The dissertation presents a comparative study of the relationship between fin de siècle and the twentieth century categorizations of the "decadent" and "degenerate" artist. Julián del Casal is analyzed as a cornerstone for such debates in three interrelated spheres: literary criticism in pre-Independence Cuba, including discussions on nationhood, art, culture, and literature; Latin American modernismo criticism, in particular the debates among writers and critics on the role of literature in fin-de-siècle Latin America; and twentieth-century literary reformulations of “decadence” among writers associated with the journal Orígenes. The dissertation combines theoretical approaches on the sociology of literature, cultural and Transatlantic theories of “decadence”, and close readings of archival material. This dissertation makes a contribution to bridging the gap between literary and cultural approaches to “decadence” as both a literary strategy and a cultural and political phenomenon. It asserts that, in order to understand the significance of “decadence” in Cuba and in the rest of Latin America, it is important to go beyond traditional approaches, which have circumscribed the study of “decadence” to the nineteenth-century, and have treated it merely as an aesthetic phenomenon. Instead, the dissertation highlights the significance of this concept, in the study of twentieth-century literature and politics, as a tool to revisit the impact of colonialism and nation-formation in Latin America.