JAVMA, Vol 230, No. 10, May 15, 2007 E global conditions have resulted in an increased role for veterinary medicine in the protection of the nation’s health, food supply, and economy. Biosecurity is the relatively new term currently applied to a very old concept: preventing the spread of disease. Controlling the spread of strictly animal diseases obviously falls within the purview of veterinary medicine, but veterinarians also play a role in public health by way of zoonotic diseases and other human-animal interactions. Federally accredited veterinarians, in particular, are responsible for preventing the movement of diseased livestock and animal products and must certify their competence in specific tasks toward that end to become so accredited. These tasks include, among others, recognition of foreign animal diseases, development of cleaning and disinfection plans, and development of disease control strategies. Methods of risk assessment, or hazard analysis, vary widely depending on the particular risk. In particular, biological risk assessment may be considered to be the identification, analysis, and characterization of disease threats. Depending on the particular agent, this may include evaluation of routes of exposure and infectious dose and consideration of the consequences of disease on individuals and populations. The eventual risk assessment may be quantitative, ordinal, or qualitative, according to the nature of the analysis. Biosecurity practices are necessarily based on risk assessments, whether formal or informal, such that the use of resources is balanced against the threat. On the 1 hand, insufficient biosecurity may result in more widespread disease. On the other hand, excessively restrictive protocols and expenditure of resources in the presence of minimal risk may lead to unnecessary stress, inefficient use of time, and depletion of limited resources. The veterinary profession is a source of unique knowledge and skills essential to national biosecurity and biological risk assessment. Although most veterinarians possess such expertise, many do not recognize they possess it or do not realize how their expertise may be applied in the areas of preparedness and response. Recognizing that there are many aspects of biosecurity and risk assessment that cannot be discussed in great detail here, the present article attempts to provide Veterinary expertise in biosecurity and biological risk assessment