Kenya's Supreme Court on Saturday upheld the victory of Uhuru Kenyatta in the March 4 presidential election, Chief Justice Willy Mutunga said.
The court unanimously ruled that the election had been fair and credible and that Kenyatta and his running mate had been "validly elected".
"The presidential election ... was conducted in a free, fair, transparent and credible manner in compliance with the provisions of the constitution and all relevant provisions of the law," Mutunga said.
"It is the decision of the court that the 3rd and 4th respondents (Kenyatta and his deputy William Ruto) were validly elected," the chief justice said.
The ruling paves the way for Kenyatta, the son of Kenya's first president and one of Africa's richest men, to be sworn in as head of state on April 9.
The six judges dismissed petitions filed by Raila Odinga, outgoing prime minister and Kenyatta's main rival in the presidential race, and by civil society groups, over what they claimed was a series of irregularities that skewed the election results.
The petitioners had called for fresh elections to be ordered.
Odinga, who has repeatedly said he will abide by the ruling of the court, even if it went against him, will hold a press briefing later Saturday.
Mutunga said the judges would make the reasons for their decision public within two weeks.
Tensions have been running high ahead of the ruling. Kenya's elections in 2007 were marred by similar complaints of fraud and descended into tribal bloodshed that killed more than 1,100 people and caused hundreds of thousands to flee their homes.
Kenyatta and Ruto both face trial at the International Criminal Court in The Hague over their alleged role in planning the 2007-2008 post-election violence.
Police were out in force on Saturday around the building housing the court in central Nairobi, with Kenya's police chief David Kimaiyo warning gatherings around the court would not be tolerated.
Just after the announcement of the decision a small group of protestors was swiftly dispersed by police, who had earlier warned that supporters would not be allowed to gather around the court.