They will be the first polls since a disputed vote in December 2007 that led to violence in which more than 1,220 people were killed. The International Criminal Court is trying to find out who was responsible for the post-election fighting.
"We are conscious that our findings may be unpopular with a section of Kenyans who have preconceived notions about the elections," said Justice Isaac Lenaola, one of three judges who made the ruling.
"But we hasten to remind Kenyans that our undertaking is not to ... suit popular opinion," he said.
The government had proposed delaying the vote by four months to December because of logistical problems, a move which prompted petitions to the court to make a ruling on the date.
The court decided that the current Parliament should be allowed to serve its full five-year term, which ends on Jan. 14, 2013, and that the elections should be held 60 days later
The constitution, endorsed by a referendum in 2010, had set Aug. 14 for the East African country's presidential and parliamentary elections.
The court also ruled that if the ruling coalition — created to end the violence after the 2007 election — were to collapse this year for any reason, the electoral commission would set a poll date within 60 days of the breakdown.
An opinion poll in October showed 53 percent of Kenyans want an August election and 38 percent a December one.
Several potential candidates have declared their interest in the presidency and many others are already mobilizing party members to vote in the elections, in which they will also choose senators, county governors and civic officials.
