AbstractThis article surveys the application of “precaution” by the United States (US) in its management of living marine resources. The US has not yet implemented the precautionary principle into its environmental legislation, but regulators, courts, and agencies often rely on precautionary approaches in applying the legislation. An overview of precaution, its background and a description of the many forms it can take is presented first, followed by an overview of the major US federal legislation intended to protect living marine resources, how regulators, courts and agencies apply precautionary approaches in applying the legislation and how federal rules allow individual states to manage living marine resources. A sampling of states and regional state alliances that have applied precautionary approaches is provided and finally a unique international agreement that applies precaution in managing the waters of the Great Lakes is assessed.