Fire broke out in the roof of a block of four properties on Balby Road on Tuesday afternoon, causing traffic chaos across the town.
Now South Yorkshire Police have said that a cannabis growing set-up was located at the property, which overlooks Westfield Park.
A spokesman said: Police were called to a property on Balby Road at around 3pm on Tuesday following reports of a fire.
"Emergency services attended and ensured that the building and residents were made safe. No injuries were reported.
"A cannabis set-up was located at the address. No arrests have been made.”
A number of fire crews descended on the scene after flames were spotted leaping from the roof of the property, which is understood to be made up of a number of flats and bedsits.
Traffic was diverted and people told to stay away from the scene as a large plume of smoke poured into the air as fire crews tackled the huge blaze as it spread through the roof void.
The road was re-opened late yesterday after Doncaster Council workers made the building safe.
The investigation is ongoing and anyone with information is asked to call 101 quoting inc 563 of 20 April.