A mysterious new respiratory illness known as severe acute respiratory syndrome (SARS) has become the most perplexing infectious disease to emerge in the 21st century. From March to May 2003, it competed daily with the war in Iraq as the most sensational media event of the moment. U.S. personnel serving in the Republic of Korea represented the largest U.S. military population at risk for SARS. With tensions growing between Pyongyang and Washington, the United States/Republic of Korea alliance could not afford to be rendered combat ineffective by SARS. To remain mission ready, the U.S. Forces Korea (USFK) commander declared a "War on SARS" and directed his medical staff to develop a plan to prevent a SARS outbreak among USFK personnel. This article outlines the USFK campaign plan for the SARS epidemic and documents lessons learned for future outbreaks of highly infectious diseases.