Ukrainian President Viktor Yanukovich's Party of the Regions is leading a parliamentary election with 30.5% of the party-list vote, an exit poll by the ICTV television station has shown.
The United Opposition bloc is second with 23.9% on the party-list vote which allocates half of 450 seats in the former Soviet republic's parliament.
Another opposition party, UDAR (Punch), is third with 14.7%.
The Ukrainian President expects to secure a parliamentary majority after the election, Borys Kolesnikov, Deputy Prime Minister and one of the Regions' leaders, said after voting ended.
"There are 225 single-seat constituencies and we see our candidates winning two thirds of them," he said after exit polls showed the Regions winning about 30% in party-list voting, in which the other 225 seats are allocated.
With Mr Yanukovich's main rival, Yulia Tymoshenko, in jail and with the West seeing the poll as a test of Ukraine's commitment to democracy, interest will focus on the judgment that international monitors will hand down tomorrow.
The government's popularity has been hit by tax and pensions policies and a failure to stamp out corruption.
It has shied away from painful reforms that could secure much-needed IMF lending to shore up an export-driven economy.
The opposition includes Ms Tymoshenko's Batkivshchyna (Fatherland) party, and a liberal party headed by boxing champion Vitaly Klitschko.
Commentators expect Regions, bankrolled by industrialists and drawing on state resources, to keep a majority in the 450-seat assembly with support possibly from communists and some independents.
"We have rebuilt the country, we have achieved stability," Mykola Azarov, Prime Minister and formal leader of the Regions, told a close-of-campaigning rally on Friday.
Mr Klitschko, the WBC world heavyweight champion, who heads the UDAR party, says he will team up with the opposition led by former economy minister Arseny Yatsenyuk to fight corruption, which they say deters entrepreneurial spirit and foreign investment.
Polling stations opened at 8am and closed at 8pm (6pm Irish time).
Of the 450 seats in the single-chamber parliament, 225 will be filled by voters casting ballots for parties to send candidates from a list.
The other half will be decided by voting for individual candidates on a first-past-the-post basis, a feature re-introduced by the Regions, which is assumed to favour the party.