Early results showed Petro Poroshenko’s bloc and that of Prime Minister Arseniy Yatseniuk each taking 22% of the vote.
The president thanked voters for backing a “democratic, reformist, pro-Ukrainian and pro-European majority”.
There was no voting in eastern areas that remain under the control of pro-Russian separatist rebels.
A number of seats in the Donetsk and Luhansk regions will remain vacant, as will those for Crimea, which was annexed by Russia in March.
The rebels plan to hold their own elections next Sunday.
The legislative polls were the first since pro-Russian former President, Viktor Yanukovych, was driven from power in February after he refused to sign an agreement on closer ties with the European Union.
With 30% of ballots counted, Mr Poroshenko’s bloc – comprising his own Solidarity Party and Udar, led by former boxer champion Vitali Klitschko – had 21.59% of the vote.
But the People’s Front of the president’s ally, Mr Yatseniuk, was fractionally ahead with 21.7%, according to the election commission.
Self Help, based in western Ukraine, was third with 10.79%, followed by the Opposition Bloc, formed by allies of Mr Yanukovych and led by former Fuel Minister Yuriy Boiki, on 9.62%.
The Radical Party of Oleh Lyashko and former Prime Minister Yuliya Tymoshenko’s Fatherland were both polling above the 5% threshold for entry into parliament, while all other parties were so far below the minimum, including for the first time the pro-Russian Communist Party.
The partial vote count published on Monday covers only 225 of the 450 seats. Results for constituency seats will not come in for a few days.
“More than three-quarters of voters who took part in the polls gave strong and irreversible backing to Ukraine’s path to Europe,” Mr Poroshenko said in televised comments.
He said that in order not to lose time, coalition consultations should start on Monday.
“We have these 10 days when we must create… the best government in Ukraine because no other government will cope with the challenges that the country is facing today,” he added.
Correspondents say that the top three performing blocs, including those of Mr Poroshenko and Mr Yatseniuk, are strongly pro-European and are likely to give the president a strong mandate to pursue democratic reforms and pursue efforts to end the conflict in the east.
Turnout was more than 52%, according to the election commission.
However, it varied widely between the east and west of the country, with some three million people in separatist-controlled areas in Donetsk and Luhansk unable to vote.
International observers meanwhile expressed “serious concerns” over the effect the violence in the east of the country had on the election, with some candidates being attacked.
Anger in eastern Ukraine at the overthrow of Mr Yanukovych turned to unrest with separatists seizing government buildings and beginning an insurgency in April.
At least 3,700 people have been killed since then, 300 of them in sporadic clashes between the Ukrainian army and separatists around Donetsk’s airport since a truce was agreed on 5 September.
The election comes amid an energy crisis, with Russia cutting off gas supplies to Ukraine in June in a dispute over unpaid bills.
Ukraine’s economy is also collapsing, with GDP forecast to fall between 7% and 10% this year.