The oaths will administered by Chief Registrar of the Judiciary Anne Amadi before Chief Justice David Maraga.
Several Heads of State and leaders are at the Kasarani Sports Stadium.
Nasa leader Raila Odinga has termed Uhuru Kenyatta’s swearing-in for the second term as a "despotic coronation".
Tens of thousands of people poured into Kasarani Sports Stadium to watch President Uhuru Kenyatta being sworn in for his second and final five-year term.
President Kenyatta, accompanied by his deputy William Ruto, were at the 60,000-seater stadium, with Mr Kenyatta's swearing in taking place just after midday.
He took both the oath of allegiance and the oath of due execution of office, before signing them.
The oaths were administered by Chief Registrar of the Judiciary Anne Amadi before Chief Justice David Maraga.
Several Heads of State and leaders were present at the Kasarani Sports Stadium ahead of his inauguration.
Some of them include South Sudan President Salva Kiir, Zambia's Edgar Lungu, Rwanda's President Paul Kagame, Djibouti's President Omar, Botswana's Ian Khama and Ethiopian Prime Minister Hailemariam Desalegn.
"Coronation"
Meanwhile, National Super Alliance (Nasa) leader Raila Odinga has termed Uhuru Kenyatta’s swearing-in for the second term as a "despotic coronation".
Speaking to the BBC on Tuesday morning, Mr Odinga said there will be no conducive environment for the international community to do business with the Kenyan government without electoral justice.
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