The Severe Acute Respiratory Syndrome (SARS) is the first severe and easily transmissible disease to emerge in the 21st century. It is caused by the infection with a coronavirus, a single strand RNA capsulated virus, recently found in a small mammalian, the masked palm civet. It is likely to represent the source of human infection. The first cases of SARS have been reported in the Chinese province of Guangdong and, since then, probable cases have been reported world wide. The clinical picture is characterized by nonspecific symptoms such as fever, cough or dyspnea in patients affected by air-space opacities (unifocal involvement in the 54.6% of cases) or distress respiratory syndrome and linked to a recent exposure to a SARS case or to a travel/residence in an affected area. The empirical therapy is based on broad-spectrum antibiotics, steroids and ribavirin, but susceptibility testing have failed to demonstrate direct anti-viral activity of ribavirin against SARS-related coronavirus in vitro. The exposure to respiratory droplets and the contact with biologic fluids (respiratory and gastrointestinal secretions) represent the most efficient transmission modality of the SARS-related coronavirus. Hand hygiene is the most simple and cost effective measure of infection control to prevent contagion, and the use of airborne, contact and droplet precaution is strictly recommended to all health care workers taking care of such patients. The spread of SARS, to less developed country with limited resource for public health programs, represent the emerging alarming threat in the new global scenario.