This thesis investigates the European Union's Humanitarian Aid policy and analyses Member States' intervention strategies to cope with humanitarian crises. There are three alternative strategies: unilateralism, full delegation, or partial delegation. This thesis argues that the characteristics of crises impact on the expediency of these strategies and influence Member States' choice. Crises are characterised by urgency, uncertainty and threat. Urgency concerns the time pressure in terms of the need to intervene rapidly; uncertainty the information at the disposal of those planning the intervention; and threat the nature, diffusion and seriousness of a crisis. This thesis discusses the costs and benefits of the intervention strategies with regard to the characteristics of a crisis. It goes on to investigate how changes in these characteristics influence the expediency of strategies. Empirical evidence shows that the strategy of delegation to the EU is preferable to unilateralism when crises are highly urgent, uncertain and threatening.