Firefighters from West Paterson found the bodies of a man and woman, both in their 70's.
The fire appears to have started just after midnight with an electrical problem in the basement of the home on Overmount Ave.
Investigators found that an electrical wire coming from the main electric box was rubbing against a metal vent pipe, wearing away the wire's insulation and sparking the fire.
Authorities say the home had smoke detectors but they were melted, so it is not clear whether they were working properly.
The identities of the victims have not yet been released.