Kenyan President Mwai Kibaki has issued a final plea for voters to avoid violence in Monday's key referendum on a new constitution.
"Reject violence and selfishness," President Kibaki said
Mr Kibaki said voters should not waste an "historic chance" and urged them to vote to adopt the document.
Campaigning has been violent since Mr Kibaki published the draft document in July with controversial changes.
It proposes more power for the president, whereas opponents want power shared with an elected prime minister.
Final mass rallies of the Yes and No camps in the Kenyan capital Nairobi on Saturday passed off without the violence many feared.
Nine people have died in campaigning in recent weeks.
In a televised address President Kibaki urged people to back the draft constitution, which if accepted will be the first time the basic law has been re-written for 40 years.
The BBC's East Africa correspondent, Karen Allen, says his opponents are angry they were not allowed to put their point on television too.
Our correspondent also says there has been a last-minute hitch at the booths, with some polling clerks threatening to go on strike unless they are paid 10 times the agreed amount for helping to count the votes.
Mr Kibaki and religious leaders have both appealed for calm.
"Let us reject violence and selfishness which could destroy our country's unity," Mr Kibaki said.
"It is our duty to ensure we conduct this vote in peace."
Polling stations open at 0700 local time (0400 GMT) and close at 1700.
The No camp held the bigger of two rallies on Saturday
Votes will be counted at the polling stations and initial results are expected later the same day.
Mr Kibaki is leading the Yes campaign under the symbol of a banana, while the opposition camp is using an orange.
The symbols were chosen by Kenya's electoral commission to aid illiterate voters.
The No camp drew about 30,000 to Saturday's final rally and the Yes camp 12,000, according to Reuters.
Presidential ally Norman Nyagah accused the No camp of wanting to foment unrest to thwart government efforts to get the charter endorsed.
But No campaigner, the roads minister Raila Odinga, accused constitution supporters of planning to incite people so that they could rig the vote.
The president has promised a new constitution since 2002 but the drafting process has seen many delays.
Opponents say his final draft reneged on previous promises.
The No camp on Sunday warned the 11.6m registered voters to be wary of intimidation and ballot stuffing. The government said such fears were baseless.
About 19,000 local observers and some 150 diplomats will monitor the vote.