Pope Francis used his weekly general audience in St Peter's square on Wednesday to criticise "fake Christians" who claim to be virtuous but "live a corrupt life".
Speaking to a crowd of thousands, he said: "These fake Christians will end up in a bad way.
"Let's think about what happens right here at home (in Italy), let's think about the so-called Christian Mafiosi (mafia).
"They have nothing Christian about them. They claim to be Christian, but they carry death in their souls. We pray for them."
Many mafia leaders invoke the names of saints in secret initiation ceremonies and members of organised crime groups in Italy, such as Sicily's Cosa Nostra and Calabria's 'Ndrangheta, see themselves as religious.
Pope Francis has on numerous occasions condemned the mafia, who he says practise "the adoration of evil".
In an interview with an Italian newspaper in 2014, he said: "Some priests tend to overlook the mafia phenomenon. But all this is changing and will change.
"Our denunciation of the mafia will not happen just once, it will be constant."
Stay up to date with the latest news stories from a Christian perspective. Sign up to our daily newsletter and receive more stories like this straight to your inbox every morning.
