Kenyatta, the 55-year-old son of the country's founding President, won a second five-year term, defeating veteran opposition leader and longtime rival Raila Odinga in a tense contest. He took the oath at Nairobi's Kasarani stadium.
While supporters cheered as he made his vows at the ceremony, the stadium police fired tear gas outside at people, who were trying to enter without a seat.
"I hereby call the elections and congratulate the victors; I hereby declare Uhuru Muigai Kenyatta and William Samoei Ruto as President-elect and Deputy President-elect respectively," Chairman of the Independent Electoral and Boundaries Commission (IEBC) Wafula Chebukati said.
However, the electoral commission said that only 39 per cent of voters turned out due to an opposition boycott.
In a speech at Nairobi's Bomas of Kenya tallying centre, Kenyatta said, "Once again as you all know, I have been here before. Hope this is for the last time, fellow Kenyans, let me say that today I as a Kenyan celebrate our resilience as a nation and the resilience of our democracy and our people."
"Any other country experiencing the turns and twists of our recent engagements would be in a tough place. I take this opportunity to thank God," he added.
The violent clashes happened between the residents of Kisumu, an opposition stronghold, and police officials after supporters of the opposition National Super Alliance (NASA) rejected President Uhuru Kenyatta's re-election. (ANI)