Flats in Hirstgate, Mexborough, had to be evacuated on Boxing Day night after an arson attack.
Edlington fire crews were called just after 10.30pm and found the kitchen of a ground floor flat was well alight but there was no-one in the property.
The fire was giving off a lot of smoke and three people in an adjacent flat were escorted to safety, while two people in the flat above were checked and found to be safe. No-one needed medical attention.
A fire service spokesman said the fire had been started deliberately.
n A fire at a house on Manor Estate, Toll Bar, Doncaster, on Boxing Day was also started maliciously but no-one was hurt.