Members of the Kristina Gelder school of dance spent two days bag-packing at Morrisons to raise money for costumes for a dance performance at Disneyland Paris later this year.
The money was taken to the school’s base at Knottingley Town Hall to be counted and banked on April 17.
By Tuesday, April 26, around £500 had been cashed in but nearly £900 remained at the premises.
And between 7pm and 7.30pm, thieves managed to get in to the room where it was being stored and stole the lot.
Miss Gelder, 49, discovered the money was missing last Wednesday morning.
She said: “My first thought was major panic. I thought someone may have just moved it but when I checked the CCTV footage and saw people coming in and taking it, I just broke down in tears.
“We have done a lot of fundraising to get that money and we were exhausted.
“To know that someone has taken it just makes me so angry. The children stood for hours bag packing. It’s really upsetting.”
Miss Gelder, who has run the dance school for more than 20 years, says she will still get the children to Disneyland in August and members of the community have come forward to help the youngsters replace the stolen cash.
Miss Gelder said: “People have been very generous and we have had various donations to replace it but I don’t like the idea that these thieves are still out there.
“We haven’t got the costumes we need for Disneyland and we are now still having to fundraise to get them.”
Police said they were investigating the theft.
A spokesman said: “The offence occurred after suspects entered the premises without permission and stole a quantity of cash before making off.
“Anyone who has information about the offence is asked to contact PC Tonge on 101.”