Three fire crews from Dearne and Rotherham stations were called at 9pm on Monday night to a fire at an unoccupied pub, The Highwoods, on Elm Road in Mexborough.
Firefighters found rubbish, tables and chairs on fire in the bar area. Wearing breathing apparatus they used hose reels to prevent the fire spreading inside the pub and managed to contain it to this one area.
The fire is believed to have been started deliberately.
Fire crews left the scene at 10:15pm.