This paper seeks to examine the issue of secession in Sudan from an international law perspective. We start by outlining the actual approach of international law towards secession of states (I). In a second part, the paper focuses on the case of the Sudan by highlighting the framework surrounding the exercise of the right to self-determination granted to the people of Southern Sudan in the form of a popular referendum in 2011 (II). Finding agreement on certain post-referendum issues (which in case of secession will amount to what is called «state succession» in international legal theory) are crucial to the sustainability of the peaceful relationship between Northern and Southern Sudan. The paper in a third part will point out international standards and issues at stake with regard to state succession and post-referendum issues in the Sudan (III).