The men died on the second floor multi-family house that was without water and electricity, The (Newark, N.J.) Star-Ledger reported.
A fourth man in the house escaped the fire uninjured, said Anthony Ambrose, chief of detectives for the prosecutor's office.
Orange police officer Anthony Holmes said the men appear to have died from burns and smoke inhalation.
The fire may have been caused by a heating device, Holmes said.
Orange city spokesman Anthony Salters called the fire a "tragedy of epic proportions."
"Mayor Warren on behalf of the City of Orange extends his sincere condolences to the family and friends of the victims," Salters said. "Homeless persons seeking shelter is a nationwide problem that highlights the need for more facilities to combat this issue."