The aim was to analyze the effects of body mass index (BMI), low-dose exposure, mixtures of persistent organic pollutants (POPs), and lipid adjustment on the relationship between POP concentrations and diabetes and prediabetes in the general adult population of Catalonia (Spain). Serum concentrations of POPs were measured by gas chromatography with electron-capture detection in 886 participants in a health interview survey. The highest concentrations of all POPs analyzed were found in subjects who had diabetes. Levels were also higher in individuals with prediabetes than in subjects without the disorder. In models adjusted by age, sex and BMI, the prevalence of diabetes and prediabetes increased in a dose-dependent manner across quartiles of PCBs 118, 138, 153, and 180, and HCB. When models were further adjusted for lipids, the associations were slightly lower and statistically significant, the ORs for the upper quartile ranging from 2.0 to 2.8 (all p-values for linear trend <0.05). Concentrations of p,p'-DDT, p,p'-DDE and β-HCH were not associated with diabetes or prediabetes. Increasing concentrations of PCBs and HCB were positively associated with diabetes and prediabetes. Only part of the association was due to age and BMI. Findings support the hypothesis that exposure to POPs may be a diabetogenic factor in both obese and nonobese individuals.