The arrests came after a probe that started in 2018 and led to a major nationwide operation.
Around 131 million euros worth of assets were seized in Tuesday’s operation and a total of 57 people are under investigation.
The 18 people arrested are allegedly members of two crime gangs and face charges that include mafia association, extortion, money-launder and self-laundering.
They are accused of aiding the Mazzarella and D’amico Camorra clans, the Mancuso and Mazzaferro ‘Ndrangheta clans and the Rome-based Senese clan.
The arrested suspects include the sons of Enrico Nicoletti, a late member of Rome’s Banda della Magliana, and of jailed Senese-clan boss Michele Senese - Antonio Nicoletti and Vincenzo Senese.
ANSA