Costco workers represented by the Teamsters have overwhelmingly voted to authorize a strike, demanding what they call a "fair contract" before their current agreement expires on January 31.
18,000 workers could walk off the job.
The International Brotherhood of Teamsters claims the vote reflects frustration over Costco's refusal to offer terms that match its record profits of $254 billion in annual revenue.
"Our members have spoken loud and clear — Costco must deliver a fair contract, or they'll be held accountable," said Teamsters general president Sean M. O'Brien.
Teamsters argued the company's management, despite its success, has failed to meet demands for fair wages and benefits.
Pickets have taken place across the country, and union leaders warned Costco that failure to negotiate an agreement could result in a strike.
Last September, Costco reported a 9% rise in sales, with a noticeable boost from port strikes and Hurricane Helene.
Costco revealed that their shoppers are getting younger and buying more gold, prompting the company to list platinum bars for sale online.
There are estimates the company is selling up to $200 million in gold a month.
