The snap election, coming eight months after a street revolt overthrew Moscow-backed president Viktor Yanukovych, is expected to result in a legislature filled with reformers and nationalists backing President Petro Poroshenko's drive to bring Ukraine closer to the West.
However, Poroshenko's party is unlikely to win a straight majority, meaning he may have to seek a coalition with more radical nationalists suspicious of his attempts to negotiate peace with pro-Russian rebels controlling a swathe of the country's industrial east.
Voters in Crimea and in separatist-controlled areas of Lugansk and Donetsk provinces -- about five million of Ukraine's 36.5 million-strong electorate -- were effectively shut out from the election. Twenty seven seats in the 450-seat parliament will remain empty.
As a result, the previously peaceful divide between the mostly Russian-speaking and Russia-leaning east and the more Ukrainian-speaking west has become a deadly -- and increasingly formal -- faultline threatening the country's future.
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For the first time since the collapse of the Soviet Union, the Communist Party was not expected to clear the five-percent barrier for entering parliament under proportional representation. Poroshenko, elected president in May with 55 percent of the vote, hopes that failure represents an irreversible political shift.
Polls show a majority of Ukrainians support economic and democratic reforms -- especially a crackdown on corruption -- leading eventually to European Union membership.
A Moscow-backed truce signed by Kiev and the separatists on September 5 has calmed the worst fighting, although there are daily violations around the largest rebel-held city Donetsk.