Polling stations opened for the first day of voting on Sunday in an election to choose a successor to the technocrat government of Mario Monti, appointed just over a year ago to save Italy from financial crisis.
Voting began at 8 a.m. and will go on to 10 p.m. (2100 GMT)Polls will re-open on Monday at 7 a.m. and remain open until 3 p.m. (1400 GMT), with the first exit polls for both the lower house and Senate expected soon afterwards.
The election, in the middle of a deep recession, is being closely watched by financial markets amid concern that it may fail to produce a clear winner capable of continuing the broad course of budget discipline and economic reform begun by Monti and backed by Italy's European partners.
The last opinion polls published before a pre-election blackout two weeks ago put a centre-left coalition led by Pier Luigi Bersani in the lead although former prime minister Silvio Berlusconi had been closing the gap.
Uncertainty over the result has been increased by a surge in support for the anti-establishment 5-Star Movement of comedian Beppe Grillo who has ridden a wave of public anger against corruption and privilege in Italy's political elite.
(Reporting by Catherine Hornby; Editing by Alison Williams)