Four crews were called to tackle a barn fire in Loxwood in the early hours of the morning.
Crews from Bognor Regis, Petworth, Horsham and Billingshurst were called at 4.43am to a barn on fire in Roundstreet Common, Loxwood, the fire service confirmed.
The barn, measuring 10 by 20 metres, was completely destroyed by the blaze, the spokesman said.
A digger at the site also has minor fire damage.
Crews left the scene at 11.03am, but officers from Sussex Police remain at the site.