Berdymukhamedov, 59, kissed the state flag three times and stood on a white sheep wool carpet symbolising a "bright path and kind deeds". The ceremony was attended by around 2,500 people.
Central Election Commission chair Gulmyrat Myradov said the inauguration would be "written in golden letters in the history of Turkmenistan", a Central Asian country that gained independence from Moscow in 1991.
"The presidential election showed the solidarity of the people and confirmed the will of the people, that our people are committed to democracy, unity and cohesion," said Myradov at the ceremony.
"Even grander, more elevated and more responsible tasks stand ahead," he said, noting that the present cabinet would be replaced by "a new team" in a month.
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His words were greeted by chants of "Glory to the protector!" which is how the state media refers to Berdymukhamedov.
The president promised to create a human rights ombudsman in a country where abuses are cited as being systematic by rights groups, and strengthen the fight against drug trafficking.
The former dentist and health minister took power in 2006 in the gas-rich country with no experience of competitive politics after the death of Turkmenistan's first president, Saparmurat Niyazov.
In Sunday's election, the incumbent leader thrashed eight other token candidates that included subordinate regional officials and the director of a government-owned oil refinery, taking 97.7 per cent of the vote.
All eight candidates vigorously applauded Berdymukhamedov at the swearing-in ceremony.
The Central Election Commission, which claimed an incredulous turnout of 97.3 per cent said yesterday that his closest rival, the chairman of the state agribusiness association, scored just over one per cent.
In recent years the country of over 5 million people has traded its traditional economic reliance on Russia for dependence on China, which buys the vast majority of its gas.
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