Alongside first responders and other professionals in disaster management, nurses are critical in public health and other roles. With the increasing threat of biological weapons of mass destruction, nurses need to clearly define their roles in biodefense. Professional nursing roles involved with biodefense include all aspects of nursing specialty particularly community health, public health, psychiatry, informacist, researchers, healthcare institution bedside nurses, and nurse practitioners. Nurses? roles are addressed in relation to pre- and post-exposure measures. The pre-exposure countermeasures include risk assessment, surveillance, personal preparedness, self and public education, disaster drills, policy development and immunization. Nurse-related post-exposure measures include disaster management, triaging, casualty management, public education, panic control, counseling, and measures to minimize agent spread like personal protective equipment (PPE) and other bio-agent specific measures. Emerging areas of nursing involvement in biodefense are biological and nursing research as promoted by the National Institute of Nursing Research (NINR). Nurse practitioners as providers are cornerstones in the defense against biological weapon because they may be the first to recognize and report military and civilian cases. This presentation will detail the past, present and emerging roles of the professional nurse in biodefense.