Susceptibility of three parasitoids, Cardiochiles nigriceps Vierick, Cotesia marginiventris (Cresson), and Microplitis croceipes (Cresson), of Heliothis virescens (F.) to field rates of various insecticides used in control of pests in cotton was determined. The fourteen insecticides used for comparisons between C. nigriceps and M. croceipes were acephate, azinphosmethyl, bifenthrin, chlorpyrifos, dicrotophos, dimethoate, cyfluthrin, cyhalothrin, cypermethrin, endosulfan, methyl parathion, oxamyl, profenofos, and thiodicarb. All of these insecticides, except for thiodicarb, were extremely toxic to M. croceipes. Treatment with the five insecticides, thiodicarb, acephate, oxamyl, azinphosmethyl and cypermethrin, resulted in higher survival for C. nigriceps adults than treatment with the other nine insecticides. Cypermethrin was less toxic to C. nigriceps females than the other three pyrethroids tested. The fourteen insecticides used for the studies on C. marginiventris included: acephate, azinphosmethyl, bifenthrin, cyhalothrin, cypermethrin, endosulfan, esfenvalerate, fipronil, methomyl, methyl parathion, oxamyl, profenofos, thiodicarb, and Pirate. Eleven of these fourteen insecticides were extremely toxic to C. marginiventris, causing 92-100% mortality of adult wasps, whereas treatment with thiodicarb, oxamyl, and acephate resulted in lower mortality of C. marginiventris males and females. For both male and female C. marginiventris, thiodicarb and oxamyl were less toxic than acephate. Esfenvalerate was the least toxic pyrethroid for C. marginiventris females. Selective use of the insecticides which resulted in higher survival could conserve these native biological control agents increasing their effectiveness.