The Feast of San Gennaro, who is best known for the miracle of his liquefying blood, fell on September 19.
It is believed that the offerings were stolen from the parish office on Sunday night and Carabinieri police are now undertaking an investigation.
The thieves also stole 500 euros from the premises used by the cathedral caretaker and video surveillance equipment.
Video footage suggests that four people may have been implicated in the theft.
With ANSA