Abstract: A fly killing composition in granular form characterized by synergistic attractant properties, an unusually long useful life, and substantial resistance to inactivation due to moisture. The composition comprises a combination base of granular, dark colored fly attractant such as fish food containing meat by-product material, in conjunction with a cooked, bright yellow, sugar-based attractant. These materials are coated with and absorb into the interstices thereof fly-toxic quantities of a mixture of 2,2-dichlorovinyl 0,0-dimethyl phosphate and 0,0-dimethyl 0-2,4,5-trichlorophenylphosphorothioate. A dusting powder applied to the insecticide impregnated particles assures that the surfaces thereof present a dull appearance notwithstanding the presence of a substantial amount of sugar in the bait formulation.