A chronology of key events
1899-1955 - South Sudan is part of Anglo-Egyptian Sudan, under joint British-Egyptian rule.
1956 - Sudan gains independence.
First civil war
1962 - Civil war led by the southern separatist Anya Nya movement begins with north.
1969 - Group of socialist and communist Sudanese military officers led by Col Jaafar Muhammad Numeiri seizes power; Col Numeiri outlines policy of autonomy for south.
1972 - Government concedes a measure of autonomy for southern Sudan in a peace agreement signed in Addis Ababa.
1978 - Oil discovered in Unity State in southern Sudan.
Second civil war
1983 - Fighting breaks out again between north and south Sudan, under leadership of John Garang's Sudanese People's Liberation Movement (SPLM), after Sudanese President Jaafar Numeiri abolishes South Sudan's autonomy.
1988 - Democratic Unionist Party - part of Sudan's ruling coalition government - drafts cease-fire agreement with the SPLM, but it is not implemented.
1989 - Military seizes power in Sudan.
2001 - Sudanese Islamist leader Hassan Al-Turabi's party, the Popular National Congress, signs memorandum of understanding with the southern rebel SPLM's armed wing, the Sudan People's Liberation Army (SPLA). Mr Al-Turabi is arrested the next day.
2002 - Talks in Kenya lead to a breakthrough agreement between southern rebels and Sudanese government on ending the civil war. The Machakos Protocol provides for the south to seek self-determination after six years.
North-south peace deal
2005 January - North/South Comprehensive Peace Agreement (CPA) ends civil war; deal provides for a permanent ceasefire, autonomy for the south, a power-sharing government involving rebels in Khartoum and a south Sudanese referendum on independence in six years' time.
2005 July - Former southern rebel leader John Garang is sworn in as first vice-president. A new Sudanese constitution which gives the south a large degree of autonomy is signed.
2005 August - South Sudanese leader John Garang is killed in a plane crash. He is succeeded by Salva Kiir Mayardiit.
2005 October - Autonomous government is formed in South Sudan, in line with the January 2005 peace deal. The administration is dominated by former rebels.
2006 November - Hundreds die in fighting centred on the southern town of Malakal - the heaviest between northern Sudanese forces and former rebels since the 2005 peace deal.
2008 March - Tensions rise over clashes between an Arab militia and SPLM in the disputed oil-rich Abyei area on the north-south divide - a key sticking point in the 2005 peace accord.
2009 July - North and south Sudan say they accept ruling by arbitration court in The Hague shrinking disputed Abyei region and placing the major Heglig oil field in the north.
2009 December - Leaders of North and South reach deal on terms of referendum on independence due in South by 2011.
2011 January - The people of South Sudan vote in favour of full independence from Sudan.
2011 February - Clashes between the security forces and rebels in southern Sudan's Jonglei state leave more than 100 dead.
2011 May - North occupies disputed border region of Abyei.
2011 June - Governments of north and south sign accord to demilitarize the disputed Abyei region and let in an Ethiopian peacekeeping force.