One person is seriously injured and three people have been injured overall, with 'a variety of injuries'.
A spokesman for Yorkshire Air Ambulance confirmed that two Air Ambulances landed at Olivers Mount in Scarborough, where a motorbike race is being held today.
A motorbike which was due to take part in the race event crashed prior to the start of the main race and hit spectators, YAS said.
Two people were flown to James Cook Hospital in Middlesbrough, while another person was taken to hospital in Scarborough by regular land ambulance.
Two rapid response vehicles, a clinical supervisor and a manager were also sent to the serious incident.