In the United States, plague poses a threat to humans from the infected animals in the endemic areas of the Western states. Plague may also be used in the near future as an agent of warfare or terrorism. Although the presentation of bubonic plague may be less of a problem, the septicemic and pneumonic forms present challenges to early diagnosis and prompt treatment. The major threat of plague as an agent of terrorism will probably be through the inhalational route. which could result in many cases of the pneumonic form, requiring early recognition and initiation of appropriate therapy. In a mass-casualty scenario, the clinician should be aware of the potential agents of biowarfare and be familiar with the treatment and prophylaxis recommendations outlined by the CDC. It is also prudent to employ universal precautions and respiratory isolation when treating patients with any unknown exposure. In endemic areas, personal protective measures such as use of insecticides, insect repellants, and prompt prophylaxis in cases of exposure to plague are recommended for reducing the incidence of infection. The author also recommends review of CDC website on bioterrorism (http://www.bt.cdc.gov) to keep informed of plague updates.