Three other workers suffered minor injuries.
The collapse happened at 227 Carlton Avenue, a four-story building, in the Fort Greene section around 9 a.m.
The building appeared to be under construction, and officials say I-beams gave way.
Two workers were trapped in the basement and had to be rescued. One was removed in cardiac arrest and was pronounced dead at the hospital. The other worker suffered a shoulder injury and was listed in serious condition with non-life threatening injuries.
They were among five men working on top floor when it collapsed underneath them. The two fell about 30 feet into the basement.
Authorities say that all the workers are accounted for.
The New York City Department of Buildings is investigating whether improper methods led to the collapse. The company, Professional Grade Construction, received permits for the work in February. Officials say there have been no complains, violations or citations since construction began.
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