MODIS data are compared to NOAA AVHRR for derivation of bio-physical parameters in the semi-arid Senegal, West Africa. The dynamic range of the two MODIS Vegetation Indices CVI and EVI is generally much larger than for the corresponding NOAA AVHRR NDVI data. Correlation analyses show that the two MODIS indices correlate better than it is the case for MODIS CVI/NOAA AVHRR NDVI. The MODIS CVI correlates better to the MODIS fAPAR than the MODIS EVI/MODIS fAPAR. This indicates that MODIS CVI is related to the bio-physical parameter fAPAR while MODIS EVI relates to LAI which is important when modelling the Net primary production.