European crime-fighters worked alongside the Italian police to dismantle the Naples-based gang, Europol said on Wednesday.
A total of 53 arrests were made in Turin and Genoa in north-west Italy, the Sicilian capital Palermo, and Avellino, Caserta and Naples in the Campania region.
Gang members are accused of “distributing counterfeit money on a worldwide scale” and producing the fake bank notes.
“The criminal group gained complete control of the international counterfeit euro market,” Europol said, using a “dense network” to distribute the cash globally.
They used code words to talk about the money, including “shoes”, and “gnocchi”, Europol spokesman Søren Pedersen told The Local.
Italian media said the group also produced a €300 bank note - which does not exist in legal tender - although Pedersen doubted such claims.
"Why would they? It adds an unnecessary risk. A €300 note would be much more suspicious, I can't see why they would make such a note," he said, explaining that the group focused on producing €20, €50 and €100 counterfeit notes.
Pedersen said Europol could not confirm whether the gang had links to Naples' Camorra mafia. "If you work in Naples as a criminal you have to have to very good connections," he said.
Europol named six European countries - Albania, Bulgaria, France, Germany, Romania and Spain - as among those worst affected by the gang's counterfeit money.
Algeria, Morocco and Tunisia also became victims of the Italian gang, while Senegal was named as another targeted country.