The vote at the facility of the package delivery company's trucking unit took place on Jan 15, but the votes were not counted until Wednesday because the National Labor Relations Board had to rule first on which workers could be included in the vote.

Following decades of failed attempts, the International Brotherhood of Teamsters last October scored its first-ever worker ballot wins at three FedEx Freight facilities. Those three facilities employ a few hundred of the trucking unit's 19,000 drivers.

But they have lost another four ballots since the initial wins and withdrawn six, including the latest, at FedEx Freight facility in Charleston, West Virginia. When the union withdraws a ballot petition, it is generally seen as a sign that the union is unlikely to win a vote.

"FedEx Freight drivers continue to reject the union and demonstrate their strong preference for a direct relationship with the company," the company said in a statement.

The Teamsters declined to comment. 

(Reporting By Nick Carey; Editing by Christian Plumb)