Comedian Beppe Grillo has shaken up Italian politics, with his party winning elections in the northern city of Parma and several smaller towns.
His Five Star movement has surged in popularity in its opposition to the euro, austerity and corruption.
His candidate Federico Pizzarotti won 60% of the vote for mayor of Parma.
Another anti-austerity candidate, Leoluca Orlando, won the vote in Palermo. He described his victory as "a slap in the face of the party system".
Mr Orlando is a former mayor in the Sicilian city who became prominent in the 1990s for his anti-mafia stance.
'Desire for change'
Beppe Grillo himself is unable to stand for election because of a 1981 court conviction.
He was found guilty of manslaughter after three passengers in his car -members of the same family - died in a crash on a mountain road.
But his party has rapidly become a major force in Italian politics, seizing on the unpopular measures of technocrat Prime Minister Mario Monti and refusing to engage with the mainstream parties.
In Parma, Mr Pizzarotti easily swept past centre-left Democratic Party (PD) rival Vincenzo Bernazzoli. His campaign budget, according to Beppe Grillo, was just 6,000 euros. There were also victories in the north-eastern coastal towns of Comacchio and Mira.
"My victory reflects Italians' desire for change," Mr Pizzarotti said.
Beppe Grillo had earlier described Parma as the "Stalingrad" of Italian politics, in reference to Hitler's decisive World War II defeat. He has now spoken of next spring's general election as "Berlin".
Considered to be anti-politics, the comic and blogger now commands up to 12% of the national vote in opinion polls.
More than 100 local authorities held votes on Sunday and Monday, and mayoral polls also took place in Genoa and L'Aquila.
Although the PD were defeated in Palermo and Parma, they were part of a coalition that won in Genoa. Other mainstream parties, the Northern League and Silvio Berlusconi's People of Freedom party, have been hit hard at the polls.
Turnout overall was relatively low and was apparently hit by poor weather and by Sunday's earthquake which struck north of Bologna and affected large areas of northern Italy.