An ornate collection box was smashed and cash from inside was stolen at Halifax Minster yesterday morning.
The culprit is thought to have sneaked inside during the 9am service and attacked the box - which was near the door - while worshippers were in the chapel.
The team at the Minster believe over £150 was taken.
They will also have to repair the collection box which was a bespoke design, made to match the Minster's 17th Century pews.
"People don't steal from churches for fun, they do it because they are desperate. We recognise that," said Vicar of Halifax Canon Hilary Barber.
Most of the time, there are people at the door of the Minster to welcome people inside.
"We've realised that it's the only time of the week when the door isn't manned," said Canon Barber.
Anyone with information about the incident should call West Yorkshire Police via 101.