Italy's President Giorgio Napolitano has invited Democratic Party deputy leader Enrico Letta to form a broad coalition government.
The BBC reports the appointment could see the end of two months of parliamentary deadlock.
Mr Letta, 46, must now form a cabinet that can win cross-party support and a vote of confidence in parliament, possibly this weekend.
An inconclusive general election in February left the country in political limbo.
Mr Letta said he had accepted the post knowing that it was an enormous responsibility and that Italy's political class "has lost all credibility".
Factions from across the political spectrum, including the People of Freedom Party of former Prime Minister Silvio Berlusconi, have indicated that they are ready to form a coalition under a figure like Mr Letta, who is seen as moderate of the left.
The BBC reports his uncle, Gianni Letta, has been Mr Berlusconi's chief-of-staff for 10 years.
Democratic Party leader Pier Luigi Bersani announced his resignation last week.
Mr Letta also said he would aim to change the course in Europe on austerity.
"European policies are too focused on austerity which is no longer enough," he said after meeting the president in Rome on Wednesday.