Hard economic times
Senior officials, including the speaker, had earlier suggested a number of dates for the election.
But most predicted it would take place in January 2010 - at the very end of the five-year mandate of Viktor Yushchenko, the president.
Ukraine is facing hard economic times amid a global financial crisis, with markets for its steel and chemical industries shrinking. The currency has suffered sharp falls in recent months.
Yushchenko said on Tuesday the economy had contracted 25-30 per cent year-on-year in the first two months of 2009.
No politician has announced an intention so far to contest the election.
Viktor Yanukovich, the opposition leader and ex-premier, leads opinion surveys, with Yulia Tymoshenko close behind.
Yushchenko trails in the surveys, his standing reduced to single figures.
Debate in the chamber had focused on whether the election was subject to amended parts of the constitution or on the document in place when Yushchenko was elected in 2004.
Yushchenko won an election amid protests against poll fraud - ushering in an era of pro-Western policies aimed at bringing Ukraine out of Russia's shadow.
Yanukovich was initially declared the winner, but the result was overturned in the courts after weeks of protests. Yushchenko won a re-run of the vote.
Yushchenko has twice appointed Tymoshenko - his ally during the Orange protests - as his prime minister, but the two have quarrelled repeatedly and are now rivals.