Mexico is the centre of origin and diversity for maize and the world’s largest, most diverse, and oldest living genetic resource for corn. Nearly sixty landraces grow in Mexico. For centuries, farmers have maintained this biodiversity on milpas, small plots cultivated with corn, beans, and squash varieties. In 2009, changes to Mexico’s biosafety law allowed biotech crop developers for the first time to experiment with genetically modified organism (GMO) corn trials in approved regions of Mexico. Since then, dozens of pilot permits have tested GMO corn strains for their tolerance to herbicides and resistance to insects and drought. Over the years, there have been concerns raised about the impact of genetically modified maize on local varieties. On January 1st of 2021, a Presidential Decree in Mexico went into effect to phase out the ‘use, acquisition, distribution, promotion, and import” of glyphosate. The Decree establishes a transition period until January 2024 to replace glyphosate with sustainable, culturally appropriate alternatives to “safeguard human health, biocultural diversity, and the environment. The Decree also obliges biosafety authorities to “revoke and refrain” from granting permits for the release into the environment of genetically modified maize seeds to protect food security and food sovereignty, native corn, traditional cornfields and the country’s biocultural wealth.