Researchers have long debated the adverse effects of exposure to polychlorinated biphenyls (PCBs) on children versus the benefits of breastfeeding. In this article, the authors provide an overview of the known health effects of PCBs in children and examine the level of evidence regarding the risk of postnatal exposure via breastfeeding. The major source of PCBs is environmental, with over 90% of human exposure through the food chain. PCB exposure in infants is predominantly via breast milk, but limited evidence exists of significant toxicity associated with this mode of transmission. Breastfeeding should, therefore, continue to be encouraged on the basis of evidence of the benefits derived from human milk coupled with inconclusive proof that lactational PCB exposure has major detrimental effects on the overall health and development of infants.