This chapter focuses on emergency response following an initial detection of an invasive plant pest or foreign animal disease (FAD) as well as the regulatory authority utilized to initiate a response. Many emergency responses will be associated with crops and livestock on farms and ranches while others may involve nurseries, forests, wildlife, and exotic animals in various urban and rural locations. The incident command system framework is typically utilized to organize response eforts. Standard response preparedness and mobilization will be discussed with a consideration of the multitude of internal and external infuences that can impact the strategy and tactics used during an outbreak. Sources of emergency funding and the critical need to manage public perception and information are also explained.