At 9pm yesterday a gun was fired through a window of a property in Victoria Road, it has been revealed.
Nobody was injured but the occupants of the house have been moved to a safe house.
The attack came the day after a gun was fired in nearby Frederick Street and on the same day that three arrests were made over that incident.
Police arrested three men, aged 24, 26 and 27, with the suspects now bailed pending further enquiries.
Detectives are searching for the culprit responsible for the second attack.
Detective Inspector Mark Monteiro, from South Yorkshire Police, said: “I understand that this will be extremely concerning for members of the Mexborough community as well as the wider general public.
“At this stage we cannot say whether the two incidents are linked, however it does appear that they were both targeted and that there is no wider threat to the community.
“Enquiries are ongoing and in the meantime there will be a high number of uniformed officers in the area as well as increased patrols.
“Residents can be reassured that we have got a number of resources in place to bring those responsible to justice.”
Call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.