Publisher Summary This chapter discusses the neurotoxicology of polychlorinated biphenyls (PCBs), polychlorinated dibenzo‐para‐dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). Prenatal exposure to PCBs and dioxins can be regarded as the chronic exposure of the developing central nervous system (CNS), and many processes of the CNS are likely to be sensitive to exposure to PCBs and dioxins, including neuronal and glial cells, neurotransmitters, and endocrine systems. The effects of prenatal exposure to PCBs and dioxins are of multifocal or diffuse nature. One of the important aspects of the neurotoxic effects of prenatal exposure to PCBs and dioxins is that the neurodevelopmental consequences of neurotoxic actions of prenatal exposure to environmental levels of PCBs and dioxins may be influenced by parental and home environmental conditions. Global measurements of cognitive and motor abilities are relatively strongly related to parental and home environmental conditions. The neurotoxic effects of perinatal exposure to PCBs and dioxins may be mediated by hormone‐disrupting properties of PCBs and dioxins—for example, in regard to steroid and thyroid hormone systems.