Cotton aphid, Aphis. gossypii is a major pest of Australian cotton due to an ability to develop resistance to the carbamate insecticide Pirimor and organophosphates generally. To test the pirimicarb and organophosphate resistance status of Australian strains of cotton aphid, the PCR method of Andrews et al (2004) was adapted by us to a real time PCR assay and restriction enzyme digest. The method was tested against 5 reference strains in which the resistance profile was known, 3 of which were used to test a double digest (both SspI and PdiI). In addition, 24 field isolates were assayed using bioassay and real time PCR. Both methods confirmed Pirimor resistance in a single isolate and showed the remaining isolates tested via both methods to be susceptible. Real time PCR has potential to replace bioassay for the routine resistance monitoring of Pirimor in cotton aphid.