The state's King Soopers and Safeway supermarkets are preparing for a possible strike by interviewing replacement workers.
The supermarket chains have held interviews in Denver, Colorado Springs, and Pueblo if contract negotiations with union employees break down.
The current contract with Local 7 of the United Food and Commercial Workers Union expires next month.
It's not clear how many replacement workers are going to be hired.
A similar strike in California ended last February.