The binary mixtures of pyrethroids cypermethrin, α-cypermethrin, ζ-cypermethrin, bifenthrin, fenpropathrin, λ-cyhalothrin, and deltamethrin plus organophosphates ethion, profenofos, chlorpyrifos, quinalphos, acephate, methamidophos, methyl parathion, and triazophos were evaluated on putatively resistant field populations ofBemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) from Pakistan using a leaf-dip bioassay. Ethion exhibited good potentiation with all the pyrethroids. Quinalphos potentiated cypermethrin, fenpropathrin, and λ-cyhalothrin but not bifenthrin. Acephate was potentiating with bifenthrin and fenpropathrin but antagonistic with ζ-cypermethrin. A potentiation effect was also found when methamidophos was mixed with bifenthrin and fenpropathrin. However, profenofos was antagonistic with cypermethrin, bifenthrin, and λ-cyhalothrin. Similarly, bifenthrin methyl parathion and deltamethrin triazophos mixtures were antagonistic when tested on several populations ofB.tabaci. Chlorpyrifos was antagonistic with cypermethrin but had an additive effect with fenpropathrin.