Voters across the country started lining up as early as 2 a.m. local time in some places, according to local media.
Analysts say the race is close because none of the front-runners polled significantly more than the other candidates. The election will go to a runoff for the first time in Kenyan history if no candidate receives more than 50% of the vote.
Odinga is part of a Kenyan political dynasty; His father Jaramogi Oginga Odinga was the first Vice President of independent Kenya.
He says he is contesting the polls for the fifth and final time, after failing in four previous attempts.
Odinga is backed by former rival President Kenyatta, who overruled his deputy Ruto for the top job.
This could be Odinga’s year, says political reporter and analyst Moses Odhiambo.
“There’s a sense that whichever side the government leans on wins. If you borrow from polls, Rye has an advantage,” Odhiambo told CNN.
Odinga’s main opponent, Ruto, describes himself as the “hustler-in-chief”, citing his humble beginnings as a chicken seller who fought his way to one of Kenya’s highest political offices.
Ruto, a former teacher with a doctorate in plant ecology from the University of Nairobi, has adopted a popular “man-of-the-people” approach designed to capture Kenya’s largest voting bloc – the youth.
And he seems to be succeeding, senior political analyst Herman Manyora told CNN: “Ruto has excited the youth … in an almost euphoric sense. This will help them turn out and vote.”
“There is a difference between me and my opponent. I have a plan, he doesn’t,” Ruto says of Odinga.
Analyst Odhiambo says that while the election will lead to a change in administration, Ruto and Odinga’s affiliation with the current government will not necessarily lead to a new political event.
“Among front-runners, people look for a balance between consistency and freshness,” Odhiambo said.
“Ruto is the deputy president and part of the current government. There is a perception that Odinga may be an extension of the current president because of the support the president has given him.”
What are the issues?
A myriad of economic issues matter to voters, from rising debt to high food and fuel prices and high levels of youth unemployment.
Analyst Manyora says many Kenyans, especially the youth, are disillusioned with the government and may boycott the election.
“There are things that can affect voting. One is the high cost of living in the country, helplessness and despair among the youth, unemployment, poverty levels and people not seeing what the politicians are doing for them,” the analyst said.
He added that while Kenya’s problems should generally motivate his countrymen to vote for the right candidates regardless of faction, they are not “angry enough”.
“One would expect that these issues would lead Kenyans to turn out in large numbers to the polls and express their anger at the high cost of living by voting for the people in charge … I don’t think Kenyans are where they are. Enough anger to translate that anger into political action. came,” Manyora told CNN.
The role of ethnicity
“The problem in this country is that tribal considerations trump everything else… most of the votes will be based on tribe; very few votes will come from serious voters,” analyst Manyora said.
Ruto is from the Kalenjin tribe and Odinga is from the Luo ethnic group.
The two traveled the country before completing their missions over the weekend, seeking support from people outside their strongholds.
Both candidates also chose their runners-up from the Kikuyu – one of Kenya’s largest voting blocs – also known as the Mount Kenya region.
Ruto is running alongside first-term MP Rigathy Gachagua while Odinga is polling alongside former justice minister and one-time presidential aspirant Martha Karuwa.
If elected, Karua will become Kenya’s first female vice president. Analyst Odhiambo says Kenyan women are excited by Odinga’s choice of running mate.
“There is a growing wave of support around women’s leadership which has been accelerated by Odinga’s selection of Martha as his running mate,” he said.
Only the Kikuyu and Kalenjin tribes have produced the country’s president, and this is the first election in which no leading candidate is a Kikuyu.
No candidate from the Luo tribe has ever won a presidential election.