Artisanal and small-scale gold mining (ASGM) is the world's largest source of anthropogenic mercury emissions and releases. These have devastating consequences for miners' health and the environment. Most of the >20 million ASGM miners worldwide are not officially recognized, registered, regulated, or protected by state laws. Formalization—the process of organizing, registering, and reforming ASGM—is mandated by the Minamata Convention on Mercury. Previous attempts to reduce mercury emissions from ASGM have largely failed. Our perspective argues that signatories to the Convention will only succeed in reducing ASGM mercury emissions and releases with comprehensive bottom-up formalization approaches centered around working with miners, and significant external funding from consumers, large mining corporations, and governments. The approximate global 5-year cost of this approach could be US$355 million (upper and lower estimate bounds: US$213–742 million) if scaled per country, or US$808 million (US$248 million–US$2.17 billion) if scaled per miner.