In January 2011, after years of civil war, the people of South Sudan voted overwhelmingly for separation from the Republic of Sudan. As part of the process of separation of the two states, people of South Sudanese origin who are habitually resident (in some cases for many decades) in what remains the Republic of Sudan are being stripped of their Sudanese nationality and livelihoods. This is happening irrespective of the relative strength of their connections to either state, and their views on which state they would wish to belong to. This summary of a forthcoming detailed legal commentary from the Open Society Initiative for East Africa (OSIEA) and AfriMAP looks at the issues created by the respective nationality laws of the two Sudans.