The projected results showed Berlusconi's coalition ahead for both the lower house and the Senate.
The 71-year-old's main rival, the centre-left leader Walter Veltroni, 52, has conceded victory.
The vote was held three years ahead of schedule after the collapse of Romano Prodi's centre-left coalition.
Veltroni told supporters: "As is the custom in all Western democracies, I telephoned Berlusconi to acknowledge his victory and wish him good luck in his work."
Berlusconi expressed "deep satisfaction" about the results, reported Ansa news agency.
Economic pinch
Although
Both candidates had promised to revitalize
Some 158 different parties contested the regional and national polls, including Berlusconi's new conservative People of Freedom (PDL) and Veltroni's recently formed Democratic Party (PD).
At the start of the election campaign, opinion polls gave Berlusconi's bloc a commanding lead, but it had narrowed as the election drew near.
At 80%, the final turnout appears to have been lower than in the last election, two years ago.
Berlusconi has served two terms as prime minister, last resigning in May 2006.
The tycoon, one of
Veltroni is a former communist who served for seven years as mayor of
The new government will be
PHOTO CAPTION
Italian PDL (Party for
BBC