Italian former Prime Minister Matteo Renzi also has casted his vote a few hours a go.
The anti-establishment Five Star Movement, ruling Democratic Party and ex-PM Silvio Berlusconi's right-wing coalition have all predicted victory.
Opinion polls were banned in the last two weeks of the campaign but surveys before that suggested Mr Berlusconi's alliance was in front but would not win a majority.
The last opinion polls before the vote put Berlusconi’s coalition in the lead with 37 percent, followed by the Five Star Movement with 28 percent and the centre-left with 27 percent.
Five Star is widely expected by pollsters to emerge as the single biggest party.
Italians will vote between between 7 a.m. and 11 p.m. for both chambers of parliament: 630 members of the Chamber of Deputies and the 315 elected members of the Senate. Both houses are elected every five years, unless parliament is dissolved early. But Italy’s voting-age are quite particular: Citizens aged 18 and older can vote for the Chamber of Deputies, but they must be at least 25 to vote for the Senate.
Tensions between far-right and anti-fascist activists have marred a gloomy campaign dominated by fears about immigration and economic stagnation.
Numerous Italians are sceptical about election promises made by the country’s parties.
