Noroviruses are the most common cause of acute gastroenteritis in the United States and are believed to be the most common cause of food borne illnesses.1 Noroviruses have avoided attention for years due to the difficulty of detection and inability to be cultured. Norovirus outbreaks have major implications for health care workers as they can occur in nursing homes and hospitals. To further complicate the picture, these viruses can infect persons of all ages which is a feature that distinguishes noroviruses from other agents. Factors that contribute to the significant impact of noroviruses include a large human reservoir, low infection dose, and the ability to be transmitted by various routes. This article provides an overview of noroviruses particularly as it relates to health care workers.