Seed saving is a historical cultural phenomenon that dates back to the beginning of agriculture itself. Seeds, because of their unique characteristics – the seed contains within itself the means for its own reproduction – have offered a particularly large stumbling block to capital accumulation. In the US, intellectual property rights legislation and Supreme Court decisions have played a profound role in overcoming these unique characteristics and have made it possible for input supply companies to extract more profit from the farm production process. Our analysis of the historical seed-saving practices of soybean farmers in the US indicates that large farms have consistently saved seed in the US – as much as 60 per cent in some years. However, with the introduction of Roundup Ready® soybeans the nature of seed saving was drastically changed. We argue that the combination of expanding intellectual property rights, ‘new’ GM technology, and the ideology of the technological treadmill have successfully overcome seeds’ inherent obstacles to capitalist accumulation. In capitalising nature's production, Monsanto and other leading seed corporations have been able to incur massive profits from the licensing of commercial seed supplies. As a result, US farmers are facing further loss of control of the farm production process.