A synergistic insecticidal composition is prepared by combining a Chloronicotynyle compound and an Organophosphorus (OP) compound. The preferred synergistically effective amount of the Chloronicotynyle compounds is an amount preferably ranging from 0.1 to 5% by weight of the composition. The preferred synergistically effective amount of the Organophosphorus (OP) compounds is an amount preferably ranging from 30 to 75% by weight of the composition. The composition also preferably includes 69.9 to 20% by weight of conventional agriculturally acceptable carrier(s) and/or excipient.