Summary : This proceedings carries presentations and discussions involving some 20 biotech and genetic resources specialists - including Mexican and invited foreign experts - on the distribution of teosinte in Mexico, the frequency and intensity of gene flow between maize and teosinte, the flow of genes from improve maize to landraces, and regulations and risk assessment for the release of transgenic maize in the center of origin of this crop and teosinte. The publication is targeted to researchers in genetic engineering, private seed company representatives, policymakers in Mexico and other countries wherein are found centers of genetic origin for crop species, and farmers who may eventually wish to sow transgenic seed.