FACTBOX: Kenyan opposition leader Raila Odinga

(Reuters) - Kenya's opposition leader Raila Odinga poses the biggest threat to President Mwai Kibaki's re-election bid in Thursday's national election.

Here are key facts about Odinga:

* Born into one of Kenya's political dynasties on January 2, 1945, in Maseno, west Kenya, the 62-year-old Odinga comes from the Luo tribe, one of the country's biggest.

* Father Jaramogi Oginga Odinga, a nationalist hero and Kenya's first vice president after independence from Britain in 1963, became a key opposition figure against the governments of founding President Jomo Kenyatta and his successor President Daniel arap Moi.

* Odinga is viewed as a firebrand by many Kenyans, an impression consolidated by remarks in a biography indicating he was a plotter in an attempted coup in 1982. Now he is trying to project a more moderate, business-friendly face.

* Educated in communist former East Germany, Odinga named his first-born son Fidel Castro. Representing Nairobi's Kibera slum, one of Africa's largest, Odinga projects himself as a champion of the poor. But he has a large business empire and is a member of Kenya's wealthy elite.

* Analysts say Odinga is unlikely to make big policy changes, but his outspoken, confrontational style would contrast with Kibaki's more reserved manner.

* Some attribute Odinga's toughness to the nine years he spent in jail under Moi for protesting at one-party rule. He served six years in solitary confinement. He was charged with treason over the coup bid, before fleeing to Norway for a brief exile.

* A former ally of Kibaki, he helped him win power in 2002 and served for three years in his cabinet before being sacked for campaigning against him in a 2005 constitutional referendum.

* Odinga's flamboyant style has seen him driving to rallies in a red Hummer H2.