The orange is the symbol of the "No" camp
Kenyans seem to have voted against a draft constitution after a campaign that has stirred bitter and sometimes violent debate, dividing the nation and the government.
After President Mwai Kibaki pushed for the charter's adoption, many voters in a country with high levels of illiteracy ignored the complex constitutional details and took the vote as a vote of confidence in his leadership.
What are the main issues?
Executive authority: The latest draft constitution waters down clauses hammered out at the National Constitutional Conference of 2003-2004. The conference called for a strong prime ministerial role but the revised draft retains a strong presidency.
Those campaigning for a "No" vote argued that power needed to be shared out, so that one person could no longer dominate the country as in the past. This, they said, would help fight corruption - a big problem in Kenya.
Religious courts: The initial draft sought the retention of Islamic courts. But protests from Christian leaders led to amendments to allow for other types, namely Christian, Hindu and traditional civil courts.
Land reform: The draft calls for radical land reform which has stirred anxiety among owners of large land tracts, especially in the fertile Rift Valley region.
Why does the vote matter?
If confirmed, the "No" vote would be a huge blow to Mr Kibaki.
The campaign also divided his cabinet, with seven ministers joining forces with the opposition to campaign against the draft.
With general elections due in 2007, a reshuffle is likely, leading to a realignment of Kenyan politics.
Why did the cabinet split?
The powerful Roads Minister, Raila Odinga, agreed to back Mr Kibaki's 2002 election campaign in return for being given the job of prime minister.
He was promised the constitution would be changed to set up this post within 100 days of Mr Kibaki coming to power, ending 39 years of rule by the Kanu party.
Three years later, a constitution was finally presented to the country but Mr Odinga was angry that the prime minister's role is not as powerful as he had thought.
Those allied to Mr Odinga feel that rather than governing through the broad alliance, which brought him to power, Mr Kibaki has ruled with a small group of trusted aides, known by critics as the "Mount Kenya mafia".
In a bizarre twist, Mr Odinga joined up with his former foes, Kanu, to oppose the constitution.
So the constitution has served as cover for deep political splits and at least nine people were killed during the campaign, some by police gunfire.
Throughout campaigning, rival groups have played on the ethnic sensitivities and loyalties of their followers and many voters cast their ballots along ethnic lines.
Who is for and who is against?
Banana group: President Mwai Kibaki led the "Yes" campaign under the symbol of a banana.
The group, also led by Vice-President Moody Awori, projects itself as reformist in outlook and says the drafting of a new constitution points to its reformist credentials. It also has a majority of support within the cabinet.
Orange group: The "No" camp claim the orange as their symbol. It brings together seven cabinet ministers and the official opposition party, Kanu.
Roads Minister Raila Odinga, Environment Minister Kalonzo Musyoka and opposition leader Uhuru Kenyatta are its most prominent members. Christian churches, Islamic leaders and civil rights groups back Orange.
The former president, Daniel arap Moi, who still wields influence in his Kalenjin community, also opposes the draft. He is not officially in the Orange team.
How does the referendum work?
Ballots are being counted at polling stations and announced on the spot. The results are forwarded to constituency headquarters.
The Electoral Commission of Kenya is required to announce the final referendum results within 48 hours of receiving results from all constituencies.
The final results are expected to be announced on 23 November. Anyone wishing to challenge the results must do so within 14 days.
The government hopes to enact the constitution by 12 December, Kenya's independence day.
What do Western donors say?
The issue soured Kenya's relations with key Western donors, UN agencies and NGOs after government officials said public resources would be used for campaigns.
Supporters of Mr Kibaki have accused some donors of meddling and funding the "No" team - charges the donors deny.
Many donors are disappointed with Mr Kibaki, who had promised to end years of corruption under Kanu and Mr Moi.
They say corruption has continued unabated - charges denied by the government, which says it takes time to change a culture of corruption.
What about the media?
Journalists have been attacked during rallies and some media groups have been banned from covering some campaign events.
Various concerns have been raised about expressions of tribalism and ethnic propaganda in some radio stations.
Who is observing?
Many local and international organisations monitored the vote. The government invited teams from the Commonwealth, the UN, EU, Carter Centre and African Union.