Resistance of cotton aphid (Aphis gossypii Glover) collected from four leading cotton producing regions and one non-cotton producing region in Shandong Province, China, in 1985, 1999, and 2004 to fenvalerate, omethoate, imidacloprid, acetamiprid, carbosulfan, and endosulfan, was determined on cotton (Gossypium hirsutum L.). Dose-response results indicate that A. gossypii became highly resistant to fenvalerate, and the resistance ratios (RRs) increased from 30–370-fold in 1985 to 370–2150-fold from different regions as compared with the susceptible population (S). A. gossypii also exhibited strong resistance to imidacloprid and acetamiprid with RRs of 17- to 97-fold in 2004. Resistance of A. gossypii to omethoate varied greatly among the five geographical regions, and the RRs ranged from 5- to 80-fold. In contrast, the resistance to carbosulfan did not significantly increase from 1999 to 2004 in all regions. The information from this study would be helpful for management of A. gossypii on cotton in those regions.