Why is Costco facing a class action lawsuit over its Kirkland Signature tequila? Reason explained

Costco is under new legal investigation after a class action lawsuit was filed by customers questioning the truthfulness of the labels on Kirkland Signature tequila bottles. This lawsuit has arisen as customer concerns grow, and it's happening not long after separate reports highlighted potential problems with some other Costco food products.

The lawsuit focuses on Costco's Kirkland Signature Tequila lineup, which features various types, including Blanco, Reposado, Añejo, Añejo Cristalino and Extra Añejo. These tequilas often come in large bottles and are advertised at 40 percent alcohol by volume. According to the labels, each tequila is crafted using “100 percent Blue Weber agave,” presenting them as top-shelf options in the tequila market.

Tequila regulations stipulate that brands must use at least 51 percent blue agave to meet legal standards. Costco labels its Kirkland tequila as having 100 percent agave content. Still, in recent times, some customers have questioned its taste and overall quality.

Costco’s Chief Legal Counsel Corey Billingsley (@brooksallison_ ) addresses the recent controversy over Kirkland Signature tequila. #FallonTonight pic.twitter.com/uVGzYIT26t

— The Tonight Show (@FallonTonight) November 19, 2025

Costco Kirkland signature tequila lawsuit: NMR testing and non-agave alcohol allegations

The issues grew after someone filed a proposed class action lawsuit on October 31 in the Southern District of Florida. The lawsuit claims that Nuclear Magnetic Resonance testing found differences between the tequila’s listed ingredients and what’s in it. Tests on Kirkland Signature Añejo Cristalino revealed a significant presence of alcohol from sources such as sugarcane or corn, not just agave.

The lawsuit claims the testing showed the product had “material amounts of ethanol not derived from agave plants.” This means it was mixed with ethanol, not made from Blue Weber agave. The complaint also mentions that these results might apply to all Kirkland tequila products, as they are said to come “from the same base spirit.”

The lawsuit accuses the company of negligence, providing false information, profiteering, and violating Florida’s Deceptive and Unfair Trade Practices Act. The plaintiffs are requesting a jury trial and are seeking both injunctive and declaratory relief from the court. They also demand compensation for everyone who bought the products, claiming they would not have paid higher prices if they knew the real contents of the tequila.

Some Kirkland bourbon and tequila products are listed as unavailable on Costco’s website. Product availability appears to vary by state. It is unclear if Costco has paused production or if the shortages are tied to the legal case.

The case has not yet been resolved. More updates are expected as the court examines the accusations and the testing outcomes.