Human exposure to persistent organic pollutants (POPs) are of major concern due to a diversity of adverse effects from prolonged exposure and bioaccumulation. Manufacturing of polychlorinated biphenyls (PCBs), a subgroup of POPs, has been prohibited for many decades, however, human exposure still occurs due to the persistent nature of the chemicals. The concentrations of the dioxin-like PCB congeners 105, 118 and 156 and the non-dioxin-like PCB congeners 28, 52, 101, 138, 153 and 180, p,p'-DDE, p,p'-DDT, o,p'-DDE, o,p'-DDT, HCB and β-HCH as well as the dioxin-like activity using the AhR transactivity assay was analysed in serum samples from Danish school children and their mothers in the European framework of the DEMOCOPHES/COPHES projects. The participants were selected from an urban and a rural area, respectively. The PCB concentrations and the AhR-TEQ (TCDD toxic equivalent) were significantly higher in school children living in the urban area compared to the rural, and for AhR-TEQ a strong correlation between the mothers and children was observed. We found a significant negative correlation between BMI and PCB serum concentrations. Finally, in the mothers, there was a positive association between age and PCB serum concentration. These results show that both PCBs and dioxin-like activity can be measured as biomarkers of exposure and effects in serum samples from children and women. The results indicate that people living in urban areas may be exposed to higher concentrations of PCBs, dioxins and dioxin-like chemicals which may lead to a greater risk of adverse effects for urban populations. This article is protected by copyright. All rights reserved.