Effective resistance monitoring underpins the Australian cotton resistance management strategy for insects and mites. We present monitoring data for two-spotted mite, Tetranychus urticae Koch and bean spider mite, Tetranychus ludeni Zacher for cotton seasons 1999-2000 and 2000-2001. Abamectin (Wizzard) propargite (Comite), diafenthiuron (Pegasus) and chlorfenapyr (intrepid) resistance were not detected however there was a worrying reduction in chlorfenapyr dose-response slope values between seasons. Bifenthrin (Talstar) resistance is increasing in both level and abundance in T.urticae but was not detected in T. ludeni. Profenofos resistance in T. urticae has dropped from a peak of 541x in 1999-2000 to 221x in 2000-2001 but would likely still give negligible control