The resistance of cotton aphid, Aphis gossypii Glover to six pyrethroid and four neonicotinoid insecticides was investigated using slide-dip technique in two field strains collected from Fayoum and Gharbia Governorates representing Upper and Lower Egypt during the cotton seasons 2005- 2007. In the case of pyrethroids, low levels of resistance were  detected for deltamethrin, lambda-cyhalothrin, esfenvalerate, alpha-cypermethrin and fenvalerate, fluctuated between 1.0-7.4-fold during 2005-2007 in both strains, while fenpropathrin showed high level of resistance recording a maximum value of 31.3-fold. In the case of neonicotinoids, low to moderate levels of resistance was observed in 2005-2007 where resistance ratios ranged between 1.2 and 7.0-fold. However, the low resistance level (1.6-fold) to imidacloprid, recorded in 2005, increased gradually to reach a maximum level of 5.3-fold in season 2007. On the other hand, the resistance levels to insecticides tested was not extremely variable between two different regions (Upper and Lower Egypt). The toxicity results of insecticides tested against the two field strains indicated that, with regard to pyrethroid, deltamethrin was the most toxic followed by esfenvalerate and lambda-cyhalothrin while fenpropathrin was the least toxic followed by fenvalerate and alpha-cypermethrin. On the other hand, the neonicotinoid, dinotefuran was the most toxic followed by acetamiprid, imidacloprid and thiamethoxam.