It happened around 6 p.m. on the 600 block of West Huntingdon Street.
Police tell Action News a 58-year-old man was found dead inside the home.
"Our heart goes out to all the folks who are affected by this-the neighborhood here, the family members. A difficult night for us here in Philadelphia," said Philadelphia Fire Commissioner Adam Thiel.
Investigators are still working to determine the cause of the blaze.
Thiel is reminding residents to take extra precautions as it gets colder.
"Please, you know, be cautious with eating, cooking, smoking, candles, all of that. And of course, please make sure that you have a smoke alarm on every floor of your home," Thiel said.
The victim has not yet been identified.