The poll will now take place on 3 November, nearly 18 months ahead of schedule.
Members of parliament voted overwhelmingly for the early poll, one day after a constitutional commission cleared the way for the move.
Prime Minister Bulent Ecevit had been fighting to hold the polls as planned in April 2004.
He had warned that early elections could hit the country's recovery from the worst recession since 1945.
But most MPs believed the only way to bring an end to more than two months of political turmoil - sparked by Mr Ecevit's poor health - was to re-elect parliament.
The Nationalist Action Party (MHP), the senior coalition party and now the largest party in parliament, swung behind early elections three weeks ago, making the momentum towards an early poll became unstoppable.
In Wednesday's debate, MHP members taunted their coalition partners in Mr Ecevit's Democratic Left Party (DSP), that none of them would receive a single seat in the new parliament.
The party leading the polls, AK or Justice and Development, is often described as pro-Islamist, but it says religion is not part of its ideology.
Turkey's powerful military, who threw an Islamic party out of government in the late-1990s, will be wary nonetheless, as will some of Turkey's Western allies, says the BBC's Ankara correspondent, Jonny Dymond.
Slow collapse
The ruling coalition began to disintegrate a few weeks ago when a string of deputies and ministers quit the party and the government in protest at Mr Ecevit's refusal to step down.
The ongoing row has also threatened to overshadow Turkey's negotiations to enter the European Union.
Mr Ecevit said the plans could be jeopardised by the early poll, as candidates were likely to focus more on their campaigns rather than on the reforms demanded by Brussels.