Good hand hygiene (HH) is critical to infection control in the ICU. Electronic HH surveillance systems are purported to improve HH practices. Such a system was recently trialed in our ICU. The system is based on radiofrequency transponders in three locations: bracelets worn by ICU personnel; on all HH product dispensers; and above each patient's bed. By correlating input from these three sources the system detects whether HH was performed before and after each patient contact. In the event that HH is not performed, the bracelet alerts the user (by vibration) in real time. This study represents a clinical validation of the system.