Congenital hearing loss continues to be a devastating and disabling affliction in our society. In an effort to promote early recognition and treatment of hearing impairment in children, the Joint Committee on Infant Hearing has established a series of risk factors that place a newborn or infant at risk for hearing loss. These factors have been selected based on either genetic evidence of inherited familial hearing loss, acquired hearing loss from either known or unknown causative agents, or multifactorial inheritance that combines genetic and non-genetic factors. Included in these risk factors are exposures to environmental agents that possess the potential to adversely affect the developing auditory system. In this article, the principal environmental teratogens and their potential impact upon the auditory system will be reviewed.