Suffolk County police say two armed masked men forced their way into the home.
At some point, the suspects and the 53-year-old homeowner exchanged gunfire.
The homeowner, identified as Steven Privitera, was shot once in the stomach.
He was rushed to Southside hospital, where he died.
So far, no arrests have been made.
Another relative who was at home said the men got away in a dark-colored Ford Explorer.