||CIMMYT has a global mandate for the improvement of wheat and maize, and it is also responsible for conserving the germplasm of these crops. CIMMYT’s germplasm improvement programs rely heavily on the free international exchange of maize and wheat seed. All concerned institutions, cooperators contributors and regulating authorities must have confidence in the safety of both imported and exported seed to facilitate such exchange. CIMMYT is fully committed to maintaining fundamental health standards in its worldwide operations. These standards are dictated at different levels by the International Plant Protection Convention (FAO 1997), by IT-PGRFA (FAO 2002), and by the CGIAR (1999). Seedborne or seed associated pathogens and pests can be carried on the seed surface (such as fungi and bacteria), in the seed (infecting the internal tissues, fungi bacteria and viruses) and with the seed (insects, nematodes, and resting spores of fungi such as bunts and sclerotia of Claviceps spp.). In all cases, regardless of the ocation on the seed or whether the pathogens can be transmitted to the newly formed plant directly from the infested seed, there are species of quarantine and economic importance. Quarantine requirements are frequently obsolete or not scientifically based. That is why it is important for CIMMYT to apply updated standards that will help to prevent pathogen dissemination around the world. At the same time, it is important to avoid alarming our collaborators and country phytosanitary authorities, when new information on the presence of a new pathogen or of the increased relevance of an already present pathogen in a certain area is obtained. It is always necessary to confirm the source and contact a reliable local plant pathologist to investigate the situation and evaluate the level of risk involved.