"The heart of Ukraine was on Independence Square," Yushchenko told tens of thousands of people in the square where crowds of his supporters kept up demonstrations for weeks. "Good people from all over the world, from far away countries, were looking at Independence Square, at us."
"This is a victory of freedom over tyranny. The victory of law over lawlessness," he said, standing in front of an orange banner erected on the Independence Monument's rotunda, a reference to the campaign color that led the winter's demonstrations to be called the "Orange Revolution."
Yushchenko, a Western-oriented reformer, took the oath of office in the Verkhovna Rada, Ukraine's parliament, placing his hand on a copy of the constitution and an antique Bible.
Some deputies repeatedly shouted "Yu-shchen-ko, Yu-shchen-ko," an echo of the chanting that filled Kiev during the showdown with his Kremlin-backed rival. Others stood stonily, not applauding, a reflection of the deep political tensions that Yushchenko will face as the country's third post-Soviet leader.
Yushchenko was declared the loser of a Nov. 21 election that international observers said was badly marred by vote fraud. Hundreds of thousands of demonstrators poured into Kiev's streets to protest the results and demonstrations went on for weeks.
The Supreme Court annulled the election and Yushchenko won a Dec. 26 court-ordered rerun, beating Prime Minister Viktor Yanukovych, then the prime minister, by 8 percentage points.
Yanukovych raised a series of legal challenges to the revote, the last of which was rejected by the high court on Thursday, paving the way for the inauguration.
Yanukovych has vowed to take his complaints to the European Court of Human Rights. The court has no enforcement mechanism, but such a move could be an unwelcome shadow on Yushchenko's intentions to push for Ukraine's closer integration with the European Union and NATO.
"The people of Ukraine had a fair election, the handover of power, the Ukrainian nation has risen," Yushchenko said in a brief address after the swearing in ceremony. "We have to work with the people and for the people."
Out in Independence Square, the huge crowd gathered for hours and spilled into surrounding streets. Many carried orange flags and wore orange ribbons tied on their winter coats.
"This is the end of the big game. After this, with Yushchenko Ukraine has the opportunity to become a real state, a real nation — not Russia's back yard," said 35-year-old Bohdan Mysorsky, one of the throng waiting in subfreezing temperatures for the speech.
Yushchenko promised to turn the country around after years of corruption, poverty and oppression, and pledged to safeguard freedom of speech.
"Ukraine has opened a new page in the history of Europe," Yushchenko said, his voice firm. "We are now in the center of Europe."
"Our place is in the European Union. My goal is Ukraine in a united Europe. Our road into the future is the road on which a united Europe is headed," said Yushchenko, his face still swollen and scarred with lesions from his dioxin poisoning in September that is widely believed to have been a deliberate attempt to take him out of contention.
"We will create new jobs. Whoever wants to work will have the opportunity to work and get an appropriate salary," he declared. "We will fight corruption in Ukraine. Taxes will be enforced, business will be transparent, ... we will become an honest nation."
In a promise clearly aimed at appeasing the country's large native-Russian-speaking population, who widely opposed him, Yushchenko said "Everyone can teach his children the language of his forefathers."
More than 40 countries were represented at the inauguration. The dignitaries included Secretary of State Colin Powell and NATO Secretary-General Jaap de Hoop Scheffer.
Also attending was Georgian Parliament Speaker Nino Burdzhanadze, a leader in the 2003 protests that forced a government change in her country and that became a model for Ukraine's demonstrators.
In contrast, Russia sent relatively low-level representation — Sergei Mironov, head of the upper house of parliament.
Powell met with Yushchenko on Sunday before the inauguration.
"The United States wants to do everything we can to help you meet the expectations of the Ukrainian people after this turmoil," Powell said at the start of the meeting.
"I'm sure that on Independence Square you will see hundreds of thousands of people with very bright eyes," Yushchenko said. "None of that would have been possible without our partners who share the same democratic values as we do, in which I include President Bush and you."
Bush called Yushchenko on Saturday to congratulate him on his election and on "democracy's victory" in Ukraine, White House spokesman Brian Besanceney said in Washington.
"The two leaders also discussed their support for the people of Iraq and for democracy in that country," Besanceney said.
Ukraine has 1,650 troops in Iraq, the fourth-largest contingent in the U.S.-led military operation. Outgoing President Leonid Kuchma has ordered them withdrawn by the end of June and Yushchenko has said he will stand by that.