The flames broke out inside a building on East 136th Street in Port Morris around 6:45 p.m.
Part of the roof collapsed, and the building is now a total loss.
FDNY officials say three firefighters suffered minor injuries.
Officials say crews are still on the scene, and drones are being used to monitor for any hot spots.
The cause of the fire is under investigation.
----------
* More Bronx news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube