The votes were seen as the last test ahead of next year's parliamentary elections.
ADVERTISEMENTItaly's centre-left parties have triumphed over the centre-right after a second round of 65 mayoral elections.
The Democratic Party (DP) -- led by former Prime Minister Enrico Letta -- won in several cities that have historically been held by right-wing parties.
"This is a result that strengthens us for the future," Letta said on Monday after the official results were announced.
Verona -- one of the former centre-right strongholds -- will be led by former Italian international footballer Damiano Tommasi. It is the first time in 15 years that a centre-left mayoral candidate won in the northern city.
"We are sorry for the cities that lost in these ballots despite the commitment of the candidates and activists," said Matteo Salvini, leader of the far-right League.
"[This was] often because of divisions and disputes within the right, as in Verona, and that should not happen again," he wrote on Facebook.
The local by-elections in Italy were mainly marked by a high abstention rate of nearly 58%.
The vote was seen as the last test for Italy's broad coalition ahead of next year's parliamentary elections.