A largely semi-desert country, Chad is rich in gold and uranium and stands to benefit from its recently-acquired status as an oil-exporting state.
However, Africa's fifth-largest nation suffers from inadequate infrastructure and internal conflict. Poverty is rife, and health and social conditions compare unfavourably with those elsewhere in the region.
Chad's post-independence history has been marked by instability and violence stemming mostly from tension between the mainly Arab-Muslim north and the predominantly Christian and animist south.
In 1969 Muslim dissatisfaction with the first president, Ngarta Tombalbaye - a Christian southerner - developed into a guerrilla war. This, combined with a severe drought, undermined his rule and in 1975 President Tombalbaye was killed in a coup led by another southerner, Felix Malloum.
Mr Malloum, too, failed to end the war, and in 1979 he was replaced by a Libyan-backed northerner, Goukouki Oueddei. But the fighting continued, this time with a former defence minister, Hissen Habre, on the opposite side.
In 1982, with French help, Mr Habre captured the capital, N'Djamena, and Mr Oueddei escaped to the north, where he formed a rival government. The standoff ended in 1990, when Mr Habre was toppled by the Libyan-backed Idriss Deby.
By the mid-1990s the situation had stabilised and in 1996 Mr Deby was confirmed president in Chad's first election.
In 1998 an armed insurgency began in the north, led by President Deby's former defence chief, Youssouf Togoimi. A Libyan-brokered peace deal in 2002 failed to put an end to the fighting.
From 2003 unrest in neighbouring Sudan's Darfur region spilled across the border, along with hundreds of thousands of Sudanese refugees. They have been joined by thousands of Chadians who are fleeing rebel fighting as well as violence between ethnic Arab and ethnic African Chadians.
Chad and Sudan accuse each other of backing and harbouring rebels, and the dispute led to severing of relations in 2006. However, since then, progress has been made towards normalising ties, with the two countries' presidents meeting for the first time in six years in 2010.
Chad became an oil-producing nation in 2003 with the completion of a $4bn pipeline linking its oilfields to terminals on the Atlantic coast. The government has moved to relax a law controlling the use of oil money, which the World Bank had made a condition of its $39m loan.
Idriss Deby, who came to power in a coup, won a third term in presidential elections in May 2006, gaining 77.5% of the vote.
The main opposition parties, who accused the president of corruption and refused to field any candidates, rejected the result. Polling went ahead despite a rebel assault on the capital three weeks before election day.
The president has also been beset by splits within his Zaghawa ethnic group and by defections and desertions in the military.
He survived a bid to topple him in April 2006, when rebels attacked the capital.
Rebels again stormed the capital in February 2008, but they were beaten back by government forces backed by French warplanes and troops offering logistics, intelligence and protection.
Idriss Deby was born in Fada, in north-east Chad, in 1952. A career army officer, he helped Hissen Habre topple Goukouki Oueddei in 1982.
In 1989 he fled to Sudan after being accused of plotting a coup. A year later his Patriotic Salvation Movement drove Mr Habre into exile and in 1991 Mr Deby was proclaimed president.
He won Chad's first post-independence presidential election in 1996 after overseeing the introduction of a multi-party constitution. He was re-elected in 2001.
In 2005 voters supported constitutional changes allowing Deby to stand for a third term.
Delayed presidential elections have been scheduled for April 2011.
A chronology of key events:
1883-93 - Sudanese adventurer Rabih al-Zubayr conquers the kingdoms of Ouadai, Baguirmi and Kanem-Bornu, situated in what is now Chad.
1900 - France defeats al-Zubayr's army.
1913 - French conquest of Chad completed; Chad becomes a colony within French Equatorial Africa.
1946 - Chad becomes a French overseas territory with its own territorial parliament and representation in the French National Assembly.
1960 - Chad becomes independent with a southern Christian, Francois - later Ngarta - Tombalbaye, as president.
1963 - The banning of political parties triggers violent opposition in the Muslim north, led by the Chadian National Liberation Front, or Frolinat.
1966 - Northern revolt develops into a fully-fledged guerrilla war.
1973 - French troops help put down the northern revolt, but Frolinat continues guerrilla operations throughout the 1970s and 1980s with the help of weapons supplied by Libya.
Libyan intervention
1975 - Tombalbaye deposed and killed in coup led by another southern Christian, Felix Malloum.
1977 - Libya annexes the northern Chadian Aouzou strip.
1979 - Malloum forced to flee the country; a coalition government headed by a Muslim northerner, Goukouni Oueddei, assumes power.
1980 - Libya sends in troops to support Oueddei in his fight against the Army of the North, led by a former prime minister, Hissene Habre.
1981 - Libyan troops withdraw at Oueddei's request.
1982 - Habre seizes power. He is later accused of mass political killings during his rule.
1983 - The Organisation of African Unity recognises Habre's government, but Oueddei's forces continue resistance in the north with Libyan help.
1987 - The combined troops of Frolinat and the Chadian Government, with French and US assistance, force Libya out of the entire northern region apart from the Aouzou strip and parts of Tibesti.
First democratic elections
1990 - Habre toppled by former ally, Idriss Deby.
1993 - National democracy conference sets up a transitional government with Deby as interim president and calls for free elections within a year.
1994 - International Court of Justice rejects Libyan claims on Aouzou and rules that Chad had sovereignty over the strip.
1996 - Deby wins Chad's first multi-party presidential election.
1997 - Deby's Patriotic Salvation Movement triumphs on legislative elections.
1998 - The Movement for Democracy and Justice in Chad, led by Deby's former Defence Minister, Youssouf Togoimi, begins armed rebellion against the government.
2001 - Senegalese court rules that upholds ruling that former Chadian President Habre should not be made to stand trial in Senegal, where he is in exile. It decided that Senegal's courts do not have the jurisdiction to try Habre on torture charges during his eight years in power in Chad.
2001 May - Deby declared winner in controversial presidential poll.
Peace deals
2002 January - Government and Movement for Democracy and Justice in Chad (MDJT) rebels sign Libyan-brokered peace deal intended to end three-year civil war.
2002 May - MDJT rebels and government forces clash in the far north; 64 are killed in the first outbreak of fighting since January's peace accord.
2003 January - Government signs peace deal with National Resistance Army (ANR) rebels, active in the east.
2003 October - Chad becomes an oil exporter with the opening of a pipeline connecting its oil fields with Cameroon.
2003 December - MDJT, government sign another peace accord. MDJT hardliners reject deal.
Darfur impact
2004 January-February - Thousands of Sudanese refugees arrive in Chad to escape fighting in Darfur region of western Sudan.
2004 April-May - Chadian troops clash with pro-Sudanese government militias as fighting in Sudan's Darfur region spills over the border.
2005 June - Voters back constitutional changes which allow the president to stand for a third term in 2006.
2005 November - Former president, Hissene Habre, is arrested in Senegal over allegations of crimes against humanity.
2005 December - Rebels attack the town of Adre, near the Sudanese border. Chad accuses Sudan of being behind the incident.
2006 January - President Deby backs a law to reduce the amount of oil money spent on development. The move angers the World Bank, which suspends loans and orders the account used to collect oil revenues to be frozen.
2006 March - Government says an attempted military coup has been thwarted.
Rebel battle
2006 April - Rebels seeking to oust President Deby battle government forces on the outskirts of the capital. Hundreds of people are killed. Chad cuts diplomatic ties with Sudan, accusing it of backing the rebels.
2006 May - President Deby is declared the winner of presidential elections. The main opposition parties boycott the poll.
2006 January-June - Thousands of refugees flee eastern areas as marauding Arab Janjaweed militia from Sudan's Darfur region penetrate deeper into Chad.
2006 July - Parliament approves the establishment of Chad's first state oil company, the Societe des Hydrocarbures du Tchad (SHT), which is expected to give Chad greater control over its energy assets.
2006 August - President Deby threatens to expel US energy giant Chevron and Malaysia's Petronas for failing to honour tax obligations, but relents after coming to an agreement with the companies.
2006 November - State of emergency imposed in eastern areas bordering Sudan's Darfur region after a spate of ethnic violence.
2006 December - Private newspapers stop publishing and several radio stations alter their programming to protest against state censorship under the state of emergency.
2007 February - UN refugee agency warns that violence against civilians in Chad could turn into a genocide.
2007 May - Chad and Sudan agree to stop conflict spilling across their borders but critics fear the agreement is unlikely to reduce the violence.
2007 August - Government, opposition agree to delay parliamentary elections by two years to 2009.
2007 September - UN Security Council authorises a UN-European Union peacekeeping force to protect civilians from violence spilling over from Darfur in neighbouring Sudan.
Emergency
2007 October - Emergency declared along eastern border and in the desert north.
Scandal as French charity tries to airlift a group of 100 ''orphans'' to Europe in what Chad describes as a smuggling operation.
2007 December - Six French aid workers are convicted of child-trafficking and sentenced to eight years' hard labour, but are then repatriated to serve their sentences at home.
2008 January - European Union approves a peacekeeping force for Chad to protect refugees from violence in Darfur.
2008 February - Rebel offensive reaches the streets of N'Djamena, coming close to the presidential palace; France sends extra troops.
Rebels are repulsed in fighting that leaves more than 100 dead.
2008 March - The presidents of Chad and Sudan sign an accord in Senegal aimed at halting five years of hostilities between the two countries.
2008 May - Violence between Chadian and Sudanese militias flares up, leading to Sudan cutting diplomatic relations and Chad responding by closing its border and cutting economic ties.
2008 July - Security forces say they killed more than 70 followers of Muslim spiritual leader Ahmat Israel Bichara, who had threatened to launch a holy war, in fighting in southeast Chad.
2009 January - Eight rebel groups unite to form new rebel alliance, the Union of Resistance Forces (UFR), with Rally of Democratic Forces leader Timan Erdimi as its leader.
2009 March - European Union peacekeepers in eastern Chad hand over to a new, larger UN force known as Minurcat.
2009 May - UN Security Council condemns a major anti-government rebel offensive in the east.
2009 November - UN accuses Dudan of supporting URF rebels in Chad with arms and ammunition.
Six international aid groups, including the International Red Cross, suspend work in eastern Chad, citing risk of their staff being abducted or killed.
Rapprochement
2010 February - President Deby and his Sudanese counterpart, Omar al-Bashir, hold talks in Sudanese capital Khartoum, in their first meeting for six years; President al-Bashir says his country is ready for full normalisation of ties.
Chad and Sudan agree to deploy joint force to monitor situation along their shared border.
2010 March - Chad agrees to let UN peacekeeping force (Minurcat) to stay on for two months beyond the end of its mandate in mid-March, despite repeated criticism of its performance.
2010 April - Chad-Sudan border reopens seven years after Darfur conflict forced its closure.
2010 June - Voter registration closes ahead of parliamentary polls in November and presidential elections in April 2011.
2010 May - UN Security Council votes to withdraw Minurcat peacekeeping force from Chad and Central African Republic, deployed to protect displaced Chadians and refugees from Sudan's Darfur.
2010 July - Sudanese president Omar al-Bashir travels to Chad to attend a meeting of regional leaders - defying two warrants for his arrest issued by the International Criminal Court.
2010 September - Much of the country hit by flooding.
2010 October - Main political parties agree new timetable for postponed presidential and parliamentary polls.
Experts meet to discuss how to protect Lake Chad, which has shrunk dramatically over past 50 years.
2011 January - Chad marks 50 years of independence from France.
2011 February - Parliamentary elections.
