Land use and land cover information are key information for Governments in developing countries. In this context, remote sensing satellites like Landsat or SPOT can provide valuable data covering several decades. We have developed a methodology to generate land cover maps with the aim to analyze changes in the last 25 years in the NW region of Senegal. In particular, we have applied the radiometric and atmospheric corrections prior to the classification algorithm or to the generation of vegetation indexes and, finally, to analyze the spatial and temporal variability, post-classification change detection techniques have been applied, providing valuable quantitative information.