Biosecurity is a set of measures to prevent, respond to and recover crops and livestock from pests and diseases that threaten the economy and environment. Comprehensive biosecurity systems help ensure food security and food safety, which is crucial for community health, competitiveness for agricultural export and conservation of natural environments. This subject studies the epidemiologic triangle consisting of the host, disease and the environment in which the disease develops, and the series of measures and practices to detect and prevent entry and spread of pests, diseases and weeds. The potential for future biosecurity mega shocks to the agricultural industry, preparedness for rapid emergency responses to an exotic incursion, and management of invasion of pests and diseases will be discussed.