摘要:This work analyzed the spatial distribution of deforestations in the Cerrado biome for the 2002 – 2009 period, aiming at the understanding of the current transformation processes in this ecosystem. More specifically, we generated deforestation warnings, in relation to the 2002 PROBIO Cerrado land-cover map, based on the use of MODIS imagery. These warnings were validated through both higher spatial resolution imagery (Landsat TM and CBERS CCD) and field inspections, which also allowed to identify the main physiognomic types affected, as well as the driving forces behind the observed clearings. The spatial analysis of the deforestation polygons indicated that about 70% of the warnings were concentrated in only 100 municipalities and that there are two active agricultural frontiers in the Cerrado: the first one along the West portion of the Bahia State up to the South of Maranhão; the other one extending from the South East of Mato Grosso to the East of Mato Grosso do Sul states. Such expansion occurs mainly in areas of dense vegetation and flat terrains, favorable to mechanized crop fields and, to a less extent, cattle ranching. The results clearly corroborate the importance of a systematic vegetation monitoring, for which moderate resolution satellite imagery has great potential and usefulness.