11 people staying at the Halfway House Inn near Wadebridge were evacuated in the middle of last night after a fire ripped through the pub.
The fire service believe the blaze was caused by the pub's tumble dryer.
Cornwall Fire and Rescue Service says crews used breathing apparatus, hose reel jets, hydrants and small tools to extinguish the fire.
Police, Ambulance, Highways, Western Power and The Red Cross were also involved at the scene.
Despite extensive damage to the back of the pub the managers hope to reopen as soon as possible.
The fire is not thought to be suspicious.