This article examines how commodity price shocks experienced by rural producers affect thedrug trade in Mexico. Our analysis exploits exogenous movements in the Mexican maizeprice stemming from weather conditions in U.S. maize-growing regions, as well as export áows of other major maize producers. Using data on over 2200 municipios spanning 1990-2010, we show that lower prices differentially increased the cultivation of both marijuana and opium poppies in municipios more climatically suited to growing maize.