Italians will cast their ballots on Sunday and Monday as they grapple with the longest recession in two decades and austerity cuts that have caused deep resentment in the eurozone's third economy.
The most likely outcome is a centre-left government led by Democratic Party leader Pier Luigi Bersani, a former communist with a down-to-earth manner who now espouses broadly pro-market economic views.
"I am very, very confident of victory," Bersani said in one of his last interviews before Saturday, when candidates are not allowed to campaign.
But the result is by no means certain and whether Bersani can form a stable coalition with a majority in both houses of parliament is in serious doubt, putting the financial markets on edge.
Outgoing premier Mario Monti wrapped up his campaign in Florence, accusing the left of being "a prisoner in its ideological straitjacket" and condemning ex-premier Silvio Berlusconi's "vulgarity" against women.
Berlusconi's vow in an official-looking letter to refund Italians an unpopular property tax levied by Monti prompted some people to queue up at post offices to claim their money.
European capitals will be watching closely as a return to Italy's years of free-wheeling public finances could spell disaster for the eurozone.
"We believe that a risk exists that after the February 24-25 elections there may be a loss of momentum on important reforms to improve Italian growth prospects," Standard & Poor's ratings agency said in a report this week.
London-based economic research group Capital Economics warned that "a hung parliament might plunge Italy and the eurozone back into crisis".
Polls open at 0700 GMT on Sunday and close at 1900 GMT. A second day of voting on Monday begins at 0600 GMT and ends at 1400 GMT, after which preliminary results will come out late on Monday.
The wild card in the election will be Beppe Grillo, a tousle-haired former comedian whose mix of invective and idealism has appealed to crowds of protest voters fed up with corrupt politicians.
Grillo's last election rally in a large square in Rome on Friday drew tens of thousands of supporters.
"This could be an important event in history," said Ruggero Moratti, a 60-year-old doctor from Florence.
"I hope Grillo will provoke a political and a civic turnaround," he said.
Antonella Ciminera, 33, said: "This is a wish come true... He has to be an opposition force."
The crowd chanted "Everyone go home!" -- a reference to Italy's discredited political class.
Bersani has said he will follow the course set by Monti, a former high-flying European commissioner roped in to replace the scandal-tainted Berlusconi who was forced to step down in November 2011.
Bersani told his last rally on Friday that his party had the "atomic bomb" of people power.
Director Nanni Moretti also turned out, saying it was time to "liberate" Italy from Berlusconi.
But a Bersani victory is far from a sure thing mainly because of the rapid rise in the polls of Berlusconi, the irrepressible 76-year-old billionaire tycoon who is still in the game even after 20 tumultuous years in Italian politics.
This is the sixth election campaign for Berlusconi, who has been prime minister three times, has survived multiple court cases, sex scandals and diplomatic gaffes and has turned into something of an international pariah.
Berlusconi has pursued a populist campaign, intimating that Italy's social misery can be blamed on a "hegemonic" Germany imposing austerity.
Several polls indicate Bersani may score only a half-victory by securing a majority in the lower house of parliament, the Chamber of Deputies, but failing to get one in the upper house, the Senate.
That would give Monti, an economics professor who is running as head of a centrist grouping, a key role as a coalition partner and could bring him back into a government with a ministerial posting.
An average of the most recent polls would give Bersani 34 percent, Berlusconi 30 percent, Grillo 17 percent and Monti around 11 percent of the vote.
Coming after the last polls were made public, Pope Benedict XVI's resignation could boost the church-going Monti and stop Berlusconi in his tracks as it has drawn away the media attention that the showman tycoon has often relied on.
The run-up to the vote has also been marked by a succession of high-profile corruption inquiries against politicians and business leaders in a period similar to one in the early 1990s that brought down Italy's entire political system.