The emergence of severe acute respiratory syndrome (SARS) and its subsequent worldwide spread challenged the global public health community to confront a novel infectious disease. The infection is caused by a coronavirus of animal origin. In this epidemic, molecular detections of SARS coronavirus RNA were shown to be useful for the early diagnosis of SARS. Although this pathogen was eradicated in humans, SARS or SARS-like viruses might reemerge from animals or from laboratory incidents. In this chapter, we describe several polymerase chain reaction (PCR) protocols for detecting SARS coronaviruses. These assays were routinely used for clinical diagnosis during the SARS outbreak.