During last 10 years, several studies confirmed that drought phenomena are affecting southern Mediterranean areas. One of the effects of a persistent drought is a modification of the vegetation cover and biomass. The aim of our research is to investigate and monitor the evolution of this phenom- enon in Sicily using remote sensing techniques. To do this, a data set of NOAA-AVHRR multispectral images, acquired monthly from 1988 to 2005, has been calibrated and processed. A time series analysis (TSA) has been applied both on the NDVI and precipitation data sets in order to study the main characteristics of vegetation distribution during the period under investigation and to compare the vegetation evolution as a consequence of the mean monthly rainfall distribution. Results confirm the existence of a correlation (with a time lag) between rainfall oscillations and the vegetation response in terms of NDVI.