Abstract : With only 2 adulticide classes left to combat an increasingly resistant adult mosquito population and the pressing need for novel larvicides with new modes of action, a call has been initiated by the United States Department of Defense (DOD) and public health agencies to develop new classes of insecticides that are affordable and efficacious in killing mosquitoes, especially resistant ones. At the United States Department of Agriculture (USDA), several research units within the Agricultural Research Service (ARS) are actively involved in discovering and developing novel insecticides. These units include the Mosquito and Fly Research Unit (MFRU) at the Center for Medical, Agricultural and Veterinary Entomology (CMAVE) located at Gainesville, Florida; the Invasive Insect Biocontrol and Behavior Laboratory (IIBBL) located at Beltsville, Maryland; and the Natural Products Utilization Research Unit (NPURU) located at Oxford, Mississippi. Funding for much of this research is provided by the DoD's Deployed War-fighter Protection (DWFP) Research Program, which seeks to develop insecticides with new modes of action for both military and civilian use. Discussed below are the insecticide research goals of these ARS units and the impressive results from their insecticide discovery programs.