The emergence of West Nile Virus (WNV) in North America has resulted in increased public awareness and utilization of insect repellents containing N,N-diethyl-m-toluamide (DEET) in the prevention of mosquito-borne disease. Regulatory reassessments in North American countries have recently been completed for insect repellents containing DEET as active ingredient, resulting in labeling changes intended to minimize unnecessary exposure to special populations, including children. This article describes those changes, and summarizes more recent data relating to the pharmacokinetics, toxicology, and epidemiology of adverse effects associated with DEET in humans.