The thesis aims to develop a theoretical perspective for studying illegal protection-seeking migration, and possible responses to this movement adopted by the receiving communities. Using the security dilemma as the framework of analysis, the discussion will be conducted through the theoretical perspective provided by emancipatory security theory. The thesis has three parts. In Part I, the insecurity experienced by illegal sub-Saharan protection-seekers during their journey will be analyzed based on some accounts publicized by various civil society organizations. Part II will develop the theoretical perspective by combining the literatures on refugee and forced migration studies, security dilemma theorizing, normative approaches in IR, and trust-building in world politics. Key concepts such as ‘protection-seeker’ and ‘cosmopolitan trust’ will be developed. In Part III, the logics of immigration security dilemma will be illustrated with special reference to illegal sub-Saharan protection-seeking migration in the EU. The thesis will conclude that Europe’s immigration security dilemma in relation to illegal sub-Saharan protection-seekers can be transcended through building cosmopolitan trust, which manifests itself as Kantian hospitality.