In P.R. China, electronic waste (e-waste) from across the world is dismantled and discarded. Concentrations of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were measured in serum from residents of an e-waste dismantling region (Guiyu, South China), where 80% of families work in e-waste recycling, and compared to a matching cohort from a nearby region where the fishing industry dominates (Haojiang). Serum concentrations of PBDEs and OCPs, but not PCBs, were significantly different in the two regions: the median sigmaPBDE concentration was 3 times higher in Guiyu than Haojiang, whereas the opposite was true for dichloro-diphenyl-trichloroethane (DDT). PBDEs typically accounted for 46% of the total organohalogen chemicals in samples from Guiyu, but 8.7% in Haojiang. The median BDE-209 concentration in Guiyu was 50-200 times higher than previously reported in occupationally exposed populations. The highest BDE-209 concentration was 3100 ng/g lipid, the highest yet reported in humans. Serum PBDE concentrations did not correlate with PCBs or OCPs, whereas PCBs and OCPs showed positive correlations, suggesting that sources of PBDEs to humans are different from PCBs and OCPs. The levels of PBDEs in individuals from Haojiang are possibly related to the recycling activity at Guiyu, through atmospheric transport.