The discovery was made just after midnight on the 1800 block of South 18th Street.
Police said family members reported that they had not heard from the woman in some time, so officers were dispatched to the location for a wellness check.
When officers arrived they found the woman's body and called in the fire department to assist.
Burned body found in South Philadelphia home
Investigators said the 49-year-old woman had severe burns to more than 80 percent of her body.
Police said it is undetermined at this time if it is a homicide.
The cause of death has not yet been determined.
The medical examiner's office will aid in the investigation.