This dissertation argues that contemporary Irish authors use the horror genre to critique postcolonial nation-states' pretensions to coherent national identities. The horror genre, with its interest in hybrid identities and constructions of monstrosity, allows a unique consideration of possible futures for recently postcolonial societies. I begin by situating contemporary authors like Patrick McCabe and Martin McDonagh historically, through comparisons to writers like J.M. Synge and Sean O'Casey who included on-stage violence to undercut an emerging stereotype of the Irish "national character" as dependent on certain religious (Catholic), political (nationalist), and geographic (rural) affiliations. This "Gaelic Romantic" stereotype remains powerful today, and contemporary authors use horrific material for reasons remarkably similar to their Irish Literary Renaissance counterparts: as part of a demythologizing project. The first chapter defines the horror genre and argues that it often is explicitly concerned with constructions of national identity, mainly due to its constructions of monstrosity as that which lies beyond the pale of an accepted "national character." My second chapter, shows that characters associated with a Gaelic Romantic construction of Irish national identity meet with a grisly, horror-film-style end when they are, quite literally, killed off. The third chapter argues that these contemporary authors believe such stereotypes of national identity should be bloodily dispatched not only because they are iv repressive and false, but also because the articulation of an ideal of what the nation is requires the simultaneous articulation of what it is not. The construction of national identity necessitates the abjection of those groups perceived as a threat to that nation, and those groups become a society's monsters. Contemporary Irish authors are both fascinated by this process and critical of it. They ultimately suggest that abjection cannot provide sufficient ground for a coherent individual or national identity. The final chapter argues that the monstrous emerges in these works as a site of possibility, and that the authors suggest that today's abjected identities must become tomorrow's full citizens of the state for a better Ireland to emerge. The necessary hybridity and fusion inherent in the monstrous provides a blueprint for conceptualizing more fluid, less atavistic identities.