Dioxins (PCDD/Fs) and polychlorinated biphenyls (PCBs) are environmentally persistent organic pollutants (POPs) that are associated with human health effects. These substances persist for long periods of time in the environment and accumulate and pass from one species to the next through the food chain. Human exposure to POPs is mainly through contaminated foods, and certain cultures or individuals whose diets include large amounts of fish or wild foods that are high in fat are particularly at risk of high exposure. In addition to the PCDD/Fs and PCBs, several other classes of contaminants behave similarly and share some common environmental fate and toxicological characteristics. These include well-known legacy contaminants such as DDT and certain chlorinated pesticides, as well as several new or emerging classes of persistent, bioaccumulative and toxic (PBT) substances. To make reliable estimates of human dietary exposure, it is important to have a robust sampling and analysis methodology and have sound knowledge about dietary preferences and food consumption patterns. In general, the highest levels of dioxins, PCBs and other PBTs are typically found globally in the fatty tissues and livers of fish and wildlife that occupy higher tropic levels in aquatic and terrestrial food chains. Toddlers and young children are typically at risk of higher exposure than adults because of their lower body weights and relatively higher food intakes. Dioxin and PCB levels in the food supply are generally decreasing, but high levels persist in some regions due to legacy contamination from industrial activity, the consequences of wartime use of defoliants, global cycling to the northern polar regions and isolated food contamination incidents. There is evidence, however, that exposure to new or emerging PBTs with dioxin-like characteristics such as certain brominated substances could be increasing in importance.