More than 25 firefighters were called to tackle a blaze at Huntingdon racecourse on Monday afternoon.
Crews from the Cambridgeshire Fire and Rescue Service attended after reports of a fire affecting hospitality boxes on the second floor of the Goodliff Stand at around 2.40pm.
The stand was safely evacuated and the fire was extinguished around 5pm.
Amy Starkey, Jockey Club Racecourses East Regional Director, said: “There has been an incident at Huntingdon racecourse this afternoon involving a fire on the second floor of the Goodliff Stand.
“The fire services responded quickly and the fire has been extinguished. The cause of the fire is yet unknown.
“All visitors on site at the time are safe and nobody has been injured as a result.
“The team at Huntingdon are working with the Cambridgeshire Fire and Rescue Service to establish the cause of the fire.
“Day-to-day business operations are unaffected. Repair works will be carried out ahead of our first meeting of the season on Thursday, October 4.”