The vote in Colorado on Tuesday was overwhelmingly against the labeling, while Oregon's was much closer.
While the defeats were hard to accept for advocates, it's not the end of the effort to get GMO foods labeled on store shelves, said Joel Warady, chief sales and marketing officer for Enjoy Life Foods, a food producing company in Schiller Park, Illinois, that shuns GMO made products.
"It does set the movement back," Warady said. "But it doesn't set back consumer sentiment on wanting GMO labeling. I think the fight will continue."
Monsanto, which is the world's biggest producer of GMO crop seeds and spent millions to defeat the two measures, was happy at the outcome.
"We're pleased that Colorado and Oregon farmers, food producers, retailers and especially consumers will not be subject to these costly measures and will not be unnecessarily economically impacted by the burden these labels would create," spokeswoman Charla Lord said in an email to CNBC.