Italian police say they have seized assets worth 600m euros (£526m) in the latest action against the mafia.
They include nearly 1,000 properties, 200 bank accounts and several companies said to belong to the Mallardos clan associated with the Camorra, the Neopolitan-based mafia.
Several people suspected of being members of the group were arrested.
Police say the syndicate is involved in a number of businesses - from betting shops to pharmaceuticals.
The assets include "around 900 properties, 23 companies and 200 bank accounts" allegedly belonging to the Mallardos, a police statement said.
Among those arrested was Feliciano Mallardo, the suspected clan boss.
"The clan's companies had seized control of entire economic sectors: from the production and distribution of coffee to betting shops to the wholesale trade in drinks and pharmaceutical products," the police said.
It said the clan also set up "numerous real estate companies" around Rome.
Barely a week goes by now without another major operation against Italy's various organised crime syndicates, says the BBC's Duncan Kennedy in Rome.
In the past year, the Italian authorities have changed their tactics by going after the assets of the mafia gangs, our correspondent says.
In another operation last month, they took control of more than 40 properties, 60 plots of land, nearly 200 vehicles and two football clubs being used by the mafia to boost their support.
The aim is to weaken the mob's financial structures, making it difficult to earn money for themselves and to pay others.