Nearly 13 million Italians voted in 1,200 cities, towns and provinces, after Mr Berlusconi had posted a message on his party's website, saying a win would "confirm and strengthen the national government".
Most media attention was focused on the mayoral race is in Milan, an important power base for the media mogul, where he campaigned hard for the incumbent candidate from his Freedom People party, Letizia Moratti. Another important city is Naples, struggling with mountains of refuse that Mr Berlusconi had promised would disappear.
Voting began yesterday and continues today, with the first results expectedthis evening.
Mr Berlusconi, 74, has been defending himself in four criminal cases. In the most sensational case, he is on trial for allegedly paying for sex with a Moroccan teenager.