According to preliminary results, members voted by a 93% to 7% margin for a strike authorization.
Ken Hall, co-chairman of the national negotiating committee, said negotiations with UPS started in February, but have moved at a slow pace. A strike would happen if a new contract is not agreed upon by July 31.
"It is time that we break the log jam at the negotiating table," said general president Jim Hoffa. "Our members deserve a strong contract that reflects the success of UPS over the past five years."
In 1997, negotiations continued past the contract expiration of July 31 and resulted in a 15-day strike. In 1993, a settlement was not reached until October, three months after the contract expired.