Matteo Renzi is expected to be offered to become Italian prime minister, as talks begin on forming a new government.
Italy’s President Giorgio Napolitano is starting consultations following the resignation of Enrico Letta.
Enrico Letta was ousted in a vote called by Florence mayor Matteo Renzi at a meeting of their centre-left Democratic Party.
Matteo Renzi, 39, would become Italy’s youngest prime minister.
Enrico Letta was under increasing pressure over Italy’s poor economic performance.
After accepting the prime minister’s resignation, Giorgio Napolitano’s office said talks would begin with political leaders on finding a replacement.
The consultations would be conducted swiftly to find an “efficient solution” and they would conclude on Saturday, the statement added.
Enrico Letta’s position became untenable once the Democratic Party backed a call for a new administration.
Matteo Renzi had argued that a change of government was needed to end “uncertainty”.
A new government should take over until the end of the current parliamentary term in 2018, he said.
Matteo Renzi had accused Enrico Letta of a lack of action on improving the economic situation, with unemployment at its highest level in 40 years and the economy shrinking by 9% in seven years.
Enrico Letta, 47, was also accused of failing to implement promised reforms of what is seen as an often corrupt and wasteful bureaucracy.
Youth unemployment has risen and Italians have grown increasingly impatient of the slow pace of reform and the continuing decline of families’ income and living standards.
Enrico Letta only lasted 10 months in the post after forming a coalition government with the centre-right last year. The prime minister, who drove himself from the presidential palace after resigning, took to Twitter to thank “all those who have helped me”.
[youtube 5ZNgExVyChc 650]