Greater Manchester police (GMP) and fire service officers were called to the address at 18:10 BST yesterday after receiving reports of a person trapped in a house fire.
Seven other people, including the baby's 25-year-old mother and several children, were saved but the baby died despite being rescued from a first floor bedroom.
The survivors were all taken to Royal Oldham hospital to be treated for smoke inhalation, while a 15-year-old girl also sustained a suspected broken ankle escaping the blaze.
"Inquiries are at an early stage and officers are currently trying to establish the cause of the fire," a GMP spokesperson said.
"Anyone who saw what happened or has any information about the incident is asked to call Oldham police on 0161 856 8940."
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.