Several insecticides were evaluated over a two year period for control of the cotton aphid (Aphis gossypii, Glover). The studies were conducted in the county of Tulare of the San Joaquin Valley. This site was chosen for its consistent infestation of cotton aphid. Results from our screening studies have shown that some insecticides are more efficacious at different times of the season. Prior to insecticide application, there were 100 aphids per leaf in the 1995 mid-season aphid control trial, 340 aphids per leaf in the 1995 late-season aphid control trial, and 80 aphids per leaf in the 1996 mid-season aphid control trial. Provado and Furadan provided excellent control of early to mid-season cotton aphid populations. Provado tank mixes provided the greatest control of mid-season aphid populations, and Temik sidedress with a broadcast application of Provado provided effective control of mid to late season aphid populations. Tank mixes of Lorsban provided the most effective control of late-season aphid populations. The "organic" treatments were not effective.