The impacts of biofuel-based commodity price shocks on wheat and maize producers and consumers in Mexico are quantified with a two-region welfare economics model of the world wheat and maize markets. This model captures the international flow of wheat and maize between Mexico and the rest of the world, enabling measurement of price and quantity changes in both Mexican and global wheat and maize markets due to supply shocks in the grain markets. The drastic shifts in supply that accompanied grain markets in 2007/2008 are used to quantify the effects on Mexican consumer and producer well-being.