Yorkshire and Lincolnshire Search and Rescue (YALSAR) discovered that more than £12,000 worth of life saving equipment had been stolen from one of its emergency vehicles last week.
Thieves made off with virtually all of the volunteer service's equipment, including expensive radios, first aid kits, a defibrillator and water rescue items.
Police revealed that the robbers attempted to make off with the vehicle that was parked at the Doncaster TA centre at Scarbrough Barracks, Sandford Road, Balby but crashed it into a garage wall, so decided to rid the converted Transit van of its contents.
Brett Gutteridge, YALSAR chairman, told The Star: "The service is voluntary, we get no government funding, so this is devastating, it's knocked us for six.
"How can someone break into an ambulance of all things and steal life saving equipment?
"It's disgusting, they've gone a step too far."
He added: "We are now faced with having to replace this equipment.
"The van was insured but not the equipment - we just couldn't afford to, it was a catch 22."
Mr Gutteridge also explained that the surrounding region will now have to rely on neighbouring search and rescue services should an emergency situation arise, slowing down response times.
"We would now appeal to the local community to help us if they can. We need their assistance to turn this around."