Nassau County police say the bag with the decomposing remains was found on the grounds of the Express Steel Supply Company in New Cassel on Monday.
It is the same site that police had searched repeatedly since 46-year-old Winsome Angela Perez was reported missing by co-workers at Chase bank branch in Wantagh in July.
On Wednesday, police said forensic tests confirmed her identity.
Since her disappearance, police say they have not been able to find her husband, who had worked at Express Steel.
The bag was found between a 40-foot steel storage container and a chain-link fence.