Field efficacy trials were conducted In 1989-90 to determine the Insecticidal activity of AC 303,630, the lead candidate of a new class of compounds known as the pyrroles, against the major Insect and mite pests of cotton. AC 303,630 applied at 0.1-0.4 lb al/acre provided commercially acceptable control of Heliothis virescens, Helicoverpa zea, Spodoptera exigua, Trichoplusia ni, Pseudoplusia lncludens, Bucculatrix thurberielia, Tetranychus urlicae T. cinnabarinus, Franklinlelia fusca, F. occidentalis, and Sericothrins variabillis. AC 303,630 provided control of pyrethroid-resistant H. virescens. When applied on a typical Hellothis/Helicoverpa spray regime, AC 303,630 provided suppression of Anthonomus grandis. Results from these studies suggest that AC 303,630 has the potential to effectively control the major insect and mite pest species In cotton. The uniqueness of chemistry and mode of action possessed by AC 303,630 make it a potential candidate for utilization in insecticide resistance management programs.