Kurbanguly Berdymukhamedov has been sworn in as Turkmenistan's new president, after winning Sunday's poll.
The election has been condemned by critics as rigged
Mr Berdymukhamedov won an overwhelming 89% of the vote, the central election commission has said.
In his inaugural address, the new president pledged to follow the ways of his predecessor Saparmurat Niyazov, but he also promised long-awaited reforms.
The polls were called after Niyazov's death in December. The autocratic leader ruled for more than two decades.
Mr Berdymukhamedov was the favourite to succeed Mr Niyazov, but human rights groups, Western diplomats and exiled Turkmen opposition leaders have condemned the election as rigged, because no opposition candidates were allowed to stand.
The announcement of Mr Berdymukhamedov's victory came during a meeting of Turkmenistan's legislative body, the People's Council.
"The people have confided their destiny in you," the head of the country's electoral commission, Murad Karryev, told Mr Berdymukhamedov.
Straight after the announcement, the new leader was sworn in, placing his hand on the constitution and flanked by soldiers.
His inauguration was greeted by rapt applause from the audience, which included senior diplomats from around Central Asia and the world, including Russian Prime Minister Mikhail Fradkov and US Assistant Secretary of State Richard Boucher.
Foreign officials have spoken of the need to maintain stability in the energy-rich nation. Turkmenistan has large reserves of natural gas, and could play a key role in plans to build an energy corridor from Central Asia to Europe.
In his inaugural speech Mr Berdymukhamedov attempted to reassure them, by saying: "According to our plans to transport energy to world markets, we will stick firmly to bilateral agreements and in future we will base our relations on mutual benefits and equal rights."
Mr Berdymukhamedov also promised "to respect all the laws and the Constitution, to work for the good of the people and the development of our country while following the way traced by Saparmurad Turkmenbashi (Mr Niyazov)."
Hint of change
Mr Niyazov's unexpected death caused consternation in Turkmenistan, because he left no designated successor.
He ruled for 21 years, tolerating no dissent as he crafted an elaborate personality cult, reduced spending on education and health care, and isolated his country from the outside world.
Voters in Sunday's polls were offered the choice of six men to take over from Mr Niyazov, all members of the ruling - and only - political party.
Despite condemning the election as rigged due to the lack of opposition candidates, analysts say there are signs that the new leadership may be willing to introduce some changes - albeit slowly.
Mr Berdymukhamedov has already called for a re-organisation of the education system, greater internet access and bigger pensions.
He has also suggested that another political party might eventually be allowed to exist.
The International Crisis Group says there are hints that the new leadership might also be considering relaxing the political repression exercised under Mr Niyazov.
The group said there were unconfirmed reports that two former ministers had been released from prison, and that some officials were discussing whether to review the cases of other political prisoners.