The joint operation involved 700 officers on the Italian side, Italy's financial police said in a statement on Tuesday.
“Seventy-five people were arrested simultaneously in Italy and in Switzerland, accused of serious crimes including mafia association, international drug trafficking, money laundering and corruption,” the Guardia di Finanza said in a statement.
The Swiss prosecutor's office said that police seized weapons and ammunition in raids in the cantons of Argovia, Solothurn, Zug and Ticino.
Six key Italian suspects, most of them resident in Switzerland, are accused of crimes including bringing counterfeit money in from Italy.
“The accused have been living for many years in Switzerland and, presumably, carried out illegal activities along with legal activities, such as investments, loans or even the management of a restaurant,” the Swiss prosecutor said.
Italian police said that the operation targeted 158 people.
“If anybody still thinks that the 'Ndrangheta is a purely Italian problem, this operation shows the opposite,” said the head of the Italian parliament's anti-mafia commission, Nicola Morra.
Interpol warned last month that the 'Ndrangheta's vast reserves of cash mean they can offer help to businesses struggling after the coronavirus lockdowns, giving the criminal group an entry into the legitimate economy.
The 'Ndrangheta, centred in Calabria region, has surpassed Sicily's more famous Cosa Nostra to become Italy's most powerful mafia group, operating across the world.
A major police sting in December against the group resulted in the arrest of 334 people, including a police colonel and a former MP.