CYTHION^® RTU is a new insecticide formulation developed by American Cyanamid Company. This new formulation contains CYTHION^® insecticide 'The Premium Grade Malathion' and once refined emulsified vegetable oil. CYTHION RTU can be applied ultra low volume or can be applied with conventional low volume application equipment using water as a carrier. CYTHION RTU has been shown in field trials to provide similar boll weevil contact and residual control as MALATHION 91% applied ultra low volume. In 1985 CYTHION RTU was sold in five cotton producing states under special local need registrations for control of boll weevil, plant bugs, fleahoppers, aphids, thrips and other cotton insect pests. This paper summarizes the toxicology and environmental fate of CYTHION RTU.