They say tests found antibiotic and other pharmaceutical residues in Whole Foods’ beef.
Farm Forward says its mission is to end factory farming.
"The presence of this residue demonstrates the cattle were treated with antibiotics or other pharmaceuticals while being raised," the complaint said.
The suit contends that consumers overpaid for beef products due to the misleading promotion, including paying a 28 per cent markup over traditional retailers for beef tenderloin steak filet mignon.
The plaintiffs seek monetary damages and an injunction to stop Whole Foods from using the "misleading" claim to sell beef.
Whole Foods has used the no-antibiotics advertising claim for a decade.