In the two-month aftermath of that chaotic election, at least 1,200 people were killed and anywhere from 300,000 to 600,000 were displaced from their homes. Odinga was compelled to form a coalition government with his challenger Mwai Kibaki to put an end to the killings.
Kibaki was initially declared the winner of that race, opposition supporters went on the rampage charging voter fraud and intimidation.
In a power-sharing compromise, Odinga became Prime Minister, while Kibaki assumed the presidency.
Four Kenyans are now facing trial in the International Criminal Court (ICC) in The Hague for conspiring to organize that flurry of violence.
Odinga is obviously fearful that such violence can happen again.
When the ethnic drums are being sounded, we know [what that means for the country],” he told the BBC.
However, Odinga also said his union with Kibaki has been beneficial to the country.
Everyone agrees that this ‘marriage’ has produced [good] offspring… so we've not done badly because we've produced a new constitution for the country and carried out substantial reforms, he said.
We've set up a very good working relationship. Most of the time when he's [Kibaki] not under the influence of the extremists on his side, I've found him to be a real gentleman.
Odinga added: We've carried out quite a bit of reforms aimed at leveling the playing field. Unfortunately we still have some politicians who believe in the past and we have seen over the last few months incitement of the public along ethnic lines… trying to Balkanize the country along ethnic lines.
Odinga, who seeks to run for president next year, cited two particular parties the Gikuyu, Embu, and Meru Association (Gema) and Kamatusa, as potential troublemakers.
Kibaki is constitutionally prohibited from running for a third term.
Separately, Deputy Prime Minister Musalia Mudavadi, a former ally of Kibaki, resigned from his Orange Democratic Movement (ODM) party in order to throw his hat into the presidential race.
Mudavadi will now run under the United Democratic Forum banner.
Another ex-Odinga ally, former Education Minister William Ruto, has also declared his candidacy for the presidency – however, his chances may be gravely compromised due to the fact that he is one of the four prominent Kenyan officials facing charges in the ICC.
Similarly, Uhuru Kenyatta, a Kibaki ally and son of Kenya's legendary founding father, Jomo Kenyatta, is also running for president and facing charges in The Hague.
Ipsos-Synovate Ltd, the global market research firm, is predicting that Odinga will win the 2013 election, based on a poll showing more than one-third (34 percent) of the Kenyan electorate favoring him.
He is followed by Kenyatta at 22 percent support, deputy President Kalonzo Musyoka, 9 percent, while Mudavadi has only 5 percent.
Kenya boasts over 70 different ethnic groups, led by the Kikuyu, who represent 22 percent of the population, Luhya (14 percent), Luo (13 percent), Kalenjin (12 percent) and Kamba (11 percent).
Kibaki is a Kikuyu, while Odinga is Luo. (Odinga has claimed that he is a cousin of US President Barack Obama).
The African Studies Center at the University of Pennsylvania noted that: “The Kikuyu, who were most actively involved in the independence and Mau Mau movements, are disproportionately represented in public life, government, business and the professions. The Luo people are mainly traders and artisans. The Kamba are well represented in defense and law enforcement. The Kalenjin are mainly farmers. While a recognized asset, Kenya's ethnic diversity has also led to disputes. Interethnic rivalries and resentment over Kikuyu dominance in politics and commerce have hindered national integration.”