The increasingly global nature of the food supply presents new challenges for assuring food safetyand responding to emergency situations. During the past two decades there has been a tremendous effort throughout the international food safety community to make decisions that are science-based; risk-based; transparent and consistent. Food safety risk managers make decisions daily in the face of uncertainty. Understanding the sources of these uncertainties is an integral part of the decision making process. It provides a means of communicating effectively the public health and economic impact of a given decision to stakeholders. This symposium will provide an overview of the sources and characterization of uncertainty and consideration when making food safety decisions and communication.