- Raila Odinga, 77, is the veteran opposition leader now backed by longtime rival Kenyatta and is running under the Azimio la Umoja-One Kenya Coalition. The former prime minister has previously lost four shots at the presidency in 1997, 2007, 2013 and 2017
Kenya goes to the polls on Tuesday in a closely fought race to elect the fifth president since independence from Britain six decades ago.
Here are some facts and figures about the vote:
Four presidential candidates
From an initial shortlist of 17, four candidates were cleared to run for president, the smallest number since multiparty democracy in the early 1990s.
The incumbent Uhuru Kenyatta has served two terms and cannot run again.
William Ruto, 55, served as a lawmaker and agriculture minister before becoming deputy president in 2013. The ambitious rags-to-riches politician is running for the United Democratic Alliance (UDA) pledging to fight for "hustlers" trying to make ends meet.
Raila Odinga, 77, is the veteran opposition leader now backed by longtime rival Kenyatta and is running under the Azimio la Umoja-One Kenya Coalition. The former prime minister has previously lost four shots at the presidency in 1997, 2007, 2013 and 2017.
George Wajackoyah, 63, a Nairobi street kid turned eccentric lawyer and former spy, is running for the Rastafarian-inspired Roots Party, campaigning on a pledge to legalise marijuana, export hyena testicles and snake venom to China.
David Mwaure, 65, is a senior lawyer and ordained minister running on the Agano (Swahili for "covenant" or "promise") Party ticket.
22.1 million voters
About 22.1 million voters are registered. Nearly 40 percent of the voters, or 8.8 million, are aged between 18 and 34, a drop since the last poll.
A total of 46,229 polling stations will be open from 6 am to 5 pm (0300 GMT to 1400 GMT).
Election of the president, for a five-year term, is by direct popular vote. The winner needs 50 percent plus one vote and at least a quarter of the votes in 24 of the 47 counties.
Kenyans will also choose 47 county governors, 47 senators, 47 woman representatives, 290 members of parliament and 1,450 county assembly members.
There are a total of 16,100 candidates.
One of the costliest polls in the region, parliament has approved a 40.9-billion-shilling ($347-million) budget for the Independent Electoral and Boundaries Commission (IEBC).
The African Union, the European Union and the Commonwealth are among those to send observers to monitor the polls.
- Biometrics and indelible ink -
At the polling station, the voter's identity is checked biometrically using an electronic system that scans their fingerprint.
Each voter receives six ballot papers, each a different colour, for each of the six different elections.
Before they leave, indelible ink is applied to the voter's finger to ensure they cannot vote again.
The IEBC says manual registers will be used as backup if the electronic system fails, a source of dispute between the rival candidates.
More than 1,100 polling stations have no access to 3G or 4G networks with the electoral body saying it will use satellite modems to ensure coverage.
- 150,000 officers -
About 150,000 officers will be deployed to ensure the safety of the polls, police chief Hilary Mutyambai said.
Polling day has been declared a public holiday, schools have been ordered closed until Wednesday, and supermarkets have urged people to stock up.
Politically driven ethnic violence broke out after the 2007 poll, killing over 1,100 people.
In 2017, dozens of people were killed. Their deaths were blamed on police brutality following the chaos and acrimony that followed the polls.
After the polls
Results are due to be announced no later than August 16 from the national tallying centre in Nairobi.
Some observers say the presidential race could be so close there may be a run-off for the first time in Kenyan history.
Any second round must be held within 30 days.
If no candidate files a challenge to the results with the Supreme Court, the winner takes office two weeks after final results are announced.
But if the court orders an annulment, a new vote must be held within 60 days.
In a historic decision in 2017, the court declared Kenyatta's win null and void after a petition by his rival Odinga because of widespread "irregularities and illegalities" in the counting process and mismanagement by the IEBC.
The incumbent went on to win the rematch after an opposition boycott.