From the countryside to the cubicle, this contribution explores vulnerabilities to genetically modified (GM) contamination of maize landraces in northern Guatemala following the DR-CAFTA (Dominican Republic-Central America-United States Free Trade Agreement). Although some industrial farmers elsewhere in Guatemala might welcome GM seeds, in this lowland refuge zone, transnational agribusiness corporations would largely face a recalcitrant and risk-averse peasantry not easily converted into reliable customers. While the unpredictability of improvisational swidden systems in this dynamic frontier zone has protected small farmers from corporate seed marketers, it also leaves them vulnerable to informal (and invisible) GM gene flow into local maize landraces. Recent changes to Guatemala's biosafety regulatory structure may compound processes of involuntary contamination despite latent citizen opposition to GM corn. Inglés