Kenyatta, 55, who is seeking a second and final term in office, gave a televised speech in a bid to assuage tensions after a final campaign week marred by the murder of a top election official and accusations of rigging by the opposition.
He urged the 19 million registered voters to turn out in great numbers, but to "do so in peace".
"After you cast your ballot, please go home," he said
His historic rival Odinga also addressed voters today, again raising fears about rigging, and warning that the deployment of at least 150,000 security forces across the country was meant to intimidate voters.
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However, he congratulated his "worthy opponent" on his campaign.
"May the stronger candidate win tomorrow," he said.
The polls are seen as a litmus test of Kenya's progress since a disputed 2007 election sparked two months of violence which left more than 1,100 dead and 600,000 displaced.
On Tuesday Kenyans will cast ballots in six different elections, choosing governors, lawmakers, senators, county officials and women's representatives in local races also rife with tension.