The ring used by Wilby Carr Community Boxing Club, Cantley was inside a Silver Ford Transit van stolen from Birch Road, Cantley on Sunday (January 23).
Police are appealing for any witnesses or people with information about the incident to contact them to help with their enquiries.
Boxing coach Colin Boyle said he had cctv evidence of four men wearing balaclavas taking the van.
Colin who has coached young boxers at the club for eight years, said: “The ring was inside as well as head guards and would cost about £5,000 to replace. It has been a big blow to the club .
"This is a vital part of the clubs income. it provides a place for children of all ages and adults to learn a skill.
" The club has a great sense of community and everyone is devastated by this.
“We transport the ring to shows and also rent it out to other clubs.
"We were meant to have a boxing show at Leeds on February 4 and a show on February 19 and I don’t see how they can go ahead now.
”The van itself is not worth a great deal but it has just had a load of work done on it. I know there have been quite a few vans stolen from the area recently.”
The club based at Wilby Carr Centre has 21 cadet boxers and is very popular with people of all ages who come to train there.
A spokesman for South Yorkshire Police said: ““We received a call at 8am on 24 January to report a van had been stolen.
“The silver Ford van is believed to have been stolen from Birch Road in Doncaster overnight on 23 January, at around 11:30pm.
“Officers have carried out enquiries and reviewed CCTV footage. The investigation will be re-looked at if new evidence or lines of enquiry become available.
“Anyone with information is asked to call 101 quoting crime reference number 14/22819/22.”