This dissertation examines illegal immigration in the Irish context. Its principal aim is to investigate how illegal immigration was responded to and discursively represented in Irish institutional texts between 2002 and 2009. An analysis of institutional texts can cast light upon how power operates and how aspects of national identity can occur in conjunction with discourses of migration. Through a Foucauldian understanding of power and identity formation, this research maintains that discourses can be utilised by those in positions of influence to exercise power and to maintain the status quo. This study identifies a large number of institutional texts: over 1,000 parliamentary texts and over 2,500 newsprint media texts. Interviews are also undertaken with politicians and civil society activists in order to complement and expand upon the institutional texts. By employing a Critical Discourse Analysis methodology, this dissertation outlines and analyzes the various ways that illegal immigration is framed in institutional texts and the argumentations (topoi) that are expressed concerning it. This research identifies five key discursive argumentations within which illegal immigrants are represented. These include the topoi ‘control’, ‘danger’, ‘humanitarian’, ‘economy’, and ‘culture’. It is evident that there is a noticeable preoccupation with controlling illegal immigration in Irish institutional texts during the eight year period under analysis. Furthermore, there is a significant level of negative discourses about illegal immigration; however, some positive discourses are also evident. Overall, this dissertation argues that these discursive representations function in the operation of power and have three broad purposes: (i) governance through the nation state rationale and the continuation of nation building processes, (ii) the maintenance of inequality in society and legitimized practices of exclusion (including the justified control of illegal immigration), and (iii) legitimized expressions of racism.