Flames broke out around 2 p.m. at a three-story dwelling on Hull Avenue in the Norwood section quickly spread to the neighboring structures on either side.
More than 140 FDNY firefighters were on the scene as they attempted to contain the blaze.
Flames could be seen shooting through windows as thick black smoke that could be seen for miles plumed into the sky.
Multiple-alarm fire in the Bronx
One injury was reported, but there was no word on that person's condition.
"I was inside the house, and I heard the window (explode) and I see a lot of people outside," said one tenant who stood outside with a small dog wrapped in a towel. "And I smelled a lot of smoke."
The Red Cross was on the scene assisting displaced residents.
FDNY Fire Marshals said that the fire was caused by an unattended candle and that there was no working smoke alarm. It was deemed to be accidental.
----------
* More Bronx news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube