Yanukovych formally gave up his powers at an inaugural parliament session in which all 450 new members of parliament were solemnly sworn in.
"I announce the renunciation of the powers of the Ukrainian government," Yanukovych said at the ceremony in which he embraced his possible replacement, Yulia Tymoshenko. She was dressed like her supporters in her party's uniform: a red blouse and white v-necked jumper.
Parliament's inauguration means that talks to form a government reach a decisive stage in this former Soviet republic that lies sandwiched between giant neighbour Russia and the countries of the European Union.
A spokeswoman for the Yulia Tymoshenko Bloc predicted that a coalition deal could be reached as early as Friday following behind-the-scenes talks.
"The coalition agreement could in principle be signed on Friday," the spokeswoman told AFP, requesting anonymity.
A leader of President Viktor Yushchenko's party Our Ukraine-Self Defence, Vyacheslav Kirilenko, also said a coalition agreement could be signed on Friday in comments reported by Interfax.
Ukraine held snap elections on September 30 in an effort to resolve months of wrangling between Yushchenko, who supports full integration with the West, including the NATO military alliance, and the more pro-Russian Yanukovych.
Pro-Western political forces took a narrow lead in the election, although Yanukovych's Regions Party took the most votes overall.
Analysts say the most likely outcome of coalition talks is an "orange" coalition of Yushchenko's party and the Yulia Tymoshenko Bloc, which together spearheaded a peaceful uprising known as the Orange Revolution in 2004.
Together the two have 228 seats out of the total 450.
If such a coalition were to be formed Tymoshenko, a former prime minister under Yushchenko, would probably return to the post.
However it is not certain that this is what Yushchenko would want. Earlier he called for Yanukovych's Regions party to be included.
Relations between the president and Tymoshenko broke down within months of him coming to power in 2005, while critics took her to task as prime minister for a series of populist economic measures.
On Friday Yanukovych again voiced hopes that his party would be included in the next government.
"I am confident" of the possibility of such an alliance, Yanukovych was quoted by Interfax as saying.