Severe acute respiratory syndrome (SARS) is a contagious viral disease caused by a novel coronavirus (SARSCoV) and transmitted through droplets and close contact [1]. Healthcare workers (HCWs) are particularly at risk when looking after SARS patients. As reported by the World Health Organization [2] more than 20% (386) of those infected with SARS in Hong Kong were HCWs. Described here are the infection control procedures undertaken at a hospital in Hong Kong when three Caesarean sections were performed on women with active maternal SARS infection. SARS-CoV infection had been confirmed by reverse transcriptase polymerase chain reaction in all three mothers prior to the time of operation. The operations were performed between 1 April and 5 April 2003. None of the HCWs (>15) involved in the three separate operations developed fever or clinical SARS within 14 days of exposure. When the operations were performed, the Centers for Disease Control and Prevention (CDC; Atlanta, Ga., USA) had not yet prepared guidelines for the prevention of SARS transmission during Caesarean sections. Since these procedures are associated with the use of suction irrigation and diathermy, it was likely that body fluid and blood would spill and evaporate into the room during the operation. Therefore, the procedures were assumed to be aerosol generating, and previously described precautions to prevent contact and airborne infection were undertaken to prevent nosocomial SARS infection [3]. Although the CDC provided guidelines for the prevention and control of SARS infection on 6 May 2003 [4], those guidelines have, to the best of our knowledge, never been tested for the procedure described here. Following are the steps and procedures we undertook to prevent HCWs in our hospital from contracting SARS. For the three Caesarean sections performed on mothers with SARS, the number of healthcare workers was limited to a minimum, with only those personnel essential to carry out the operation, neonatal resuscitation, and cleanup being involved (i.e., 2 senior obstetricians, 2 senior neonatologists, 1 senior anaesthetist, 1 theatre assistant, a team of 4 senior midwives, and 2 cleansing staff). A nurse supervisor was designated as in-charge and was responsible for monitoring the other HCWs with regard to the use of personal protective equipment (PPE), cleansing of the room, sterilising the equipment and transferring the patients. She ensured all HCWs had fit-tested their respirators. She was also responsible for testing the portable high-efficiency particulate air filter (HEPA) units (Air-Mate PAPR; USA), checking the batteries, and training other HCWs on the proper use of the HEPA units. All unnecessary instruments were removed from the operating theatre. Extra laparotomy instruments were prepared to deal with possible intra-operative complications. Two bags of blood were made available in the theatre for the operation. Disposable instruments were used if available. To avoid spillage of blood, drapes with plastic bags on the sides were used. An operating theatre separate from the main theatre block was designated for this type of surgery in order to minimise contamination of the main theatre. The door of the operating theatre was kept closed during the operation, except when participating personnel entered or left the room. In order to keep the number of entrances and exits to a minimum during the operation, most of the equipment was prepared before the patient arrived. The air circulation was adjusted to 20 exchanges per minute. Negative pressure was created within the operating theatre relative to the adjacent room or hallway; thus, S. F. Wong ()) · K. M. Chow · Y. P. Leung · A. Chiu · P. W. Y. Lam · L. C. Ho Department of Obstetrics and Gynaecology, Maternal Fetal Medicine Unit, Princess Margaret Hospital, Lai Chi Kok, Kowloon, Hong Kong e-mail: shellwong@hotmail.com Tel.: +1-852-29901111 Fax: +1-852-29903488