In the framework of an investigation about frost damage that occurred 1987 in Northern Greece a new index, the modified NDVI (mNDVI), was developed. Within a joint bilateral German-Greek-Cooperation project the Greek partner investigated SPOT images and the German partner mainly evaluated Landsat TM images to estimate frost damages in agriculture with a remote sensing approach. The first applications of the new mNDVI are described in this paper and show very promising results.