Maria Carmela Lanzetta, mayor of Monasterace since May 2011, said the decision was “painful, but necessary”, Corriere della Sera reported.
During her term Lanzetta’s car was shot at and her pharmacy burned down.
She was described by local news website, Calabria Ora, as a victim of “intimidation for her commitment to anti-mafia work”.
The mayor had asked councillors to take legal action against a group known for causing damage to property in the town, but the idea was rejected by her colleagues, Corriere said.
She tendered her resignation to Laura Boldrini, president of the Chamber of Deputies, who she was due to meet later this week.
Monasterace sits in the heartland of the 'Ndrangheta mafia, described by Europol as “among the richest and most powerful organized crime groups at a global level”. The group centres its power in the hamlets, villages and towns of Calabria.