Malian farmers have accumulated knowledge about managing millet and sorghum seed over thousands of years in the Sahel. In response to climatic changes in this harsh environment, they have selected the varieties that continue to perform best. Millet and sorghum are the food staples for a majority of rural Malians, although rice is preferred in the Niger delta and in urban areas. While most producers of these crops are subsistence oriented, active and well-integrated grain markets confirm that some farmers produce surpluses and some regions export. Millet and sorghum seed are traded principally through social networks in noncash transactions, and most exchanges involve noncertified seed. The right to millet and sorghum seed, and having one’s own seed, are strong customary norms in the villages studied. For a farmer to be without seed or to exchange seed for cash carries social stigma.