Since the outbreak of cholera in Peru in January 1991, the disease has spread to other Latin American countries and on several occasions has been imported into the United States. In order to assess the risk of transmission of cholera by water in the United States, an ad hoc committee from the Centers for Disease Control (CDC) and the US Environmental Protection Agency (USEPA) prepared a report (on which this article is based) on the etiology of cholera, the history of outbreaks, symptoms and treatment, transmission and survival, analysis of clinical and water specimens, and prevention of epidemics through water treatment and monitoring. The report also describes the steps that have been taken by CDC and USEPA in South America and recommends future action. Includes 20 references.