PURPOSE: To provide an insecticide composition containing 1-(2,6-dichlorobenzoyl)-3-(4-trifluoromethyl-2-thiazolyl)urea and an organophosphoric acid ester as active components, and having excellent synergistic insecticidal effect.

CONSTITUTION: The objective composition contains (A) 1-(2,6-dichlorobenzoyl)-3- (4-trifluoromethyl-2-thiazolyl)urea of formula which has the activity to kill the vermin of Lepidoptera and Coleoptera by inhibiting the hatching of egg and the ecdysis of larva when applied to the egg or larva of the vermin, and weak and slow activity as insecticide and (B) an organophosphoric acid ester of a compound having insecticidal activity. The weight ratio of A:B is preferably 1:5W0.2, and the components are applied after or without mixing. The organophosphoric acid ester is e.g. phosphates, phosphorothioate, phosphorodithioate, phosphonate, phosphoroamide, etc.