Move will enable Pakistan’s president to be sworn in as a civilian leader.
The oath was taken at the Aiwan-e-Sadr presidential palace one day after Musharraf stepped down as the head of Pakistan’s military.
Wearing a dark traditional tunic, he pledged to uphold the constitution and to do his utmost to preserve and protect the nation.
Abdul Hameed Dogar, the chief justice Musharraf hand-picked after purging the supreme court when he imposed emergency rule on November 3, administered the oath to Musharraf.
Musharraf said that general elections would take place on January 8 “come hell or high water”.
“I am not a fan of Musharaf, but I can see that he has Pakistan’s interest at heart when he says he wants to bring real democracy to the country.”
Jinah, Tamil Nadu, India
“We want democracy, we want human rights, we want stability, but we will do it our way,” he said in his first speech as civilian president.
“We understand our society, our environment, better than anyone in the West.”
Al Jazeera’s Kamal Hyder, reporting from Islamabad, said Musharraf blamed Ifikhar Chaudhry, the former chief justice of the supreme court, for “derailing” the path to democracy.
Hyder said: “[But] critics will tell you that this is false, and is being used to justify the current state of emergency.”
Musharraf also welcomed the return from exile of Benazir Bhutto and Nawaz Sharif, both former prime ministers.
However, neither were present at the ceremony and it remains unclear whether the changeover would defuse the threat of a boycott of the elections.
Such a move would undercut Musharraf’s effort to legitimise his rule through a democratic ballot.
Meanwhile, Sharif has said that Musharraf’s oath of office had no legitimacy and he demanded the reinstatement of judges sacked under the emergency.
In the city of Lahore, about 250 lawyers in black suits clashed with police outside the city’s main court.
Both sides hurled bricks at each other.
“We don’t accept Musharraf even without his uniform. He has to go,” said Malik Mohammad Arshad, a lawyer.
His eye swollen and head bleeding after begin hit by a brick.
Lawyers have led widespread opposition to Musharraf since he dimissed Chaudhry in March.
George Bush, the US president, praised Musharraf as “an absolute reliable partner in dealing with extremists and radicals” and hailed his decision to bow to quit as army chief.
Bhutto said on Wednesday that Musharraf had met one of her key demands, but said that “we are not in a hurry to accept Pervez Musharraf as a civilian president”.