An estimated 18,000 Costco employees are members of the International Brotherhood of Teamsters, and 85% of them voted to strike.

Thousand of Costco Teamsters across the U.S. are preparing to strike by the end of the month if the company does not present a "fair contract offer," the union says.

Despite Costco claims it has a stable “cared-for employee base,” over 18,000 employees disagree. Costco Teamsters have voted to strike on Jan. 31.