This chapter presents part of the diagnostic studies that were conducted to evaluate the on-farm, in situ and ex situ conservation status of plant genetic resources for food and agriculture (PGRFA) in Mesoamerica, from Mexico to Panama. The assessment of the potential impact of anthropogenic climate change on the conservation of a set of Mesoamerican crop species and their wild relatives are discussed. The results of this assessment are also used to identify priority areas for on-farm and in situ conservation in Mesoamerica.