Ali Akhmedov, the executive secretary of Aliyev's New Azerbaijan Party, talking to supporters in downtown Baku, the capital, said: "Ilham Aliyev has won."
"His victory is a victory of the Azeri people," he said.
Shortly after polls closed at 7pm (1400 GMT), hundreds of the president's jubilant supporters streamed into the streets to celebrate, while cars flying Azeri flags and bearing portraits of the president clogged traffic in the capital.
Turnout for the election was said to be high by state authorities, even though many opponents to Aliyev boycotted the vote, accusing Azerbaijani authorities of persecuting the opposition, muzzling the media and fixing previous polls.
The electoral commission said that 64.9 per cent of those eligible had voted by about 5pm (1200 GMT).
The names of six other candidates appeared alongside Aliyev on the ballot, but all were loyal to the authorities and some had not even bothered to campaign.
Azerbaijan has one of the fastest-growing economies in the world.
Fuelled by energy exports, and despite widespread corruption, the country's economy grew by 26 per cent last year.
The strategic, oil-rich country has been seen as a nation struggling to balance ties with the US and Russia, as Moscow and Washington vie for its allegiance.
The president is the son of Heydar Aliyev, the Caspian state's previous president, who dominated political life in the country for more than 30 years.
Despite criticism of his democratic record, Washington considers Aliyev as a key energy partner.
Azerbaijan is the starting point for a strategic corridor of pipelines delivering oil and gas from the Caspian Sea to Turkey and on to Western markets.