Exposure to persistent organic pollutants (POPs) has been reported as a potential risk factor for diabetes in adults. However, effect modifications by sex and age, especially among Asian populations, have seldom been investigated. In the present study, we assessed associations of major POPs exposure including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), with diabetes in Korean adults ( = 1,295), a subset of the Korean National Environmental Health Survey (KoNEHS) Cycle 3 (2015-2017). In the adult population, serum levels of dichlorodiphenyltrichloroethanes (DDTs) and PCB167 showed an increased odds ratio (OR) for diabetes. When stratified by gender, associations became stronger and more consistent in women: In women, serum levels of OCPs including ,'-DDT, ,'-dichlorodiphenyldichloroethylene (,'-DDE), and ΣOCPs and mono-ortho PCBs, such as PCB118 and PCB157, were significantly associated with diabetes. In the male participants, however, no significant positive associations were detected. When stratified by a cutoff age of 50 years, most studied POPs except PBDEs, i.e., ,'-DDT, ,'-DDE, PCB118, PCB157, PCB167, PCB138, and PCB153, showed significant associations with diabetes, in the older adults. In the younger group, however, no measured POPs showed a significant positive association. Effects of endogenous sex hormones or interaction of POPs on aryl hydrocarbon receptors may partly explain the observed differences by gender and age, although further experimental confirmations should follow. Our findings show that POPs exposure at the current levels is associated with diabetes among general Korean adults, and such associations could be modified by gender and age.