Mass at Santa Maria di Montesanto in Naples, Italy, was constantly blighted by mobile phones ringing and beeping according to the parish priest.
Father Michele Madonna's requested permission from local police to fix the £40 device on the wall of the church.
According to the Daily Mail he said: "I had put signs up asking people to switch off their phones after having services disrupted.
"Phones were always going off during Mass and at other events like funerals which just wasn't on.
"What really annoyed me is that when it first started people would switch off their phones in embarrassment now they are cupping their hands over the receiver and carrying on talking.
"I bought the jammer from a local electrical store and asked the police if it was OK and they said it was - it's great as it has stopped the problem but some of the local shops aren't happy."
The priest is now facing criticism from local business owners who say it is causing them problems with credit card readers.