Abstract: The present invention provides a new insecticide formulation based on cyclodextrin characterised in that the active substance (insecticide and/or insect growth regulator), and a compound synergistic with the active substance, are complexed simultaneously with cyclodextrin. The formulation presents as a solid or as a solid/oil composition, and is soluble or completely emulsifiable in water or in aqueous mixtures of water miscible solvents. The activity of the present formulations was found to be greater than that of a mixture of the two active components each complexed separately with cyclodextrin, for the same dose. The preparation process of said formulation and its use as an insecticide in agriculture, for veterinary use or to eliminate household insects, are further aspects of the present invention.