Technical Abstract: Rift Valley fever (RVF) is a mosquito-borne viral disease with significant health and economic impacts to domestic animals and humans in much of sub-Saharan Africa. Human infections are believed to occur mainly from mosquito bites and from infectious aerosols. The available strategies for protection of humans are limited to use of mosquito repellents and other mosquito vector control. Epidemic disease can probably be prevented by vaccination of domestic animals which serve as virus amplifiers for arthropod transmission; however, there are no licensed vaccines available for use in the United States. Epizootics and epidemics of RVF are closely linked to the occurrence of the warm phase of the El Niño/Southern Oscillation (ENSO) phenomenon. We have developed a monitoring and risk mapping system using normalized difference vegetation index (NDVI) times series data derived from the Advanced Very High Resolution Radiometer (AVHRR) instrument on polar orbiting National Oceanographic and Atmospheric Administration (NOAA) satellites to map areas with a potential for an RVF outbreak in sub-Saharan Africa. This system is an important tool for local, national and international organizations involved in the prevention and control of animal and human disease, permitting focused and timely implementation of disease control strategies several months before an outbreak. A Geographic Information System (GIS)-based remotely sensed early warning system for potential RVF vectors in the U.S. and elsewhere is being developed. Mosquito forecasting information will be disseminated throughout the U.S., granting several months warning before conditions are suitable for elevated mosquito populations, permitting targeted implementation of mosquito control, animal quarantine and vaccine strategies in time to lessen or prevent animal and human disease.