The toxicity of carbamate, organophosphorus and pyrethroid insecticides was determined by the attracticide method to field populations of pink bollworm, Pectinophora gossypiella in cotton-growing areas of Texas, Arizona, California, Mexico and China. A gradual increase in tolerance to pyrethroids was correlated with high use of these compounds in California. Many populations susceptible to pyrethroid insecticides were found except in Torreon, Mexico, where tolerance to pyrethroids prevents their use for pink bollworm control. A resistance management program for insecticides used in control of pink bollworm is now a possibility and will require considerable cooperation at the grower level.