Surveillance is an essential component of an effective infection prevention and control program. This chapter discusses the history, evolution, and use of surveillance programs in healthcare settings. It outlines the steps that should be used when designing and evaluating a surveillance program; emphasizes the importance of using sound epidemiological and statistical principles; and stresses the use of surveillance data to improve the quality of healthcare. It reviews factors that affect surveillance programs in healthcare facilities, such as the changing healthcare delivery system, emerging and reemerging infectious diseases, outbreaks and pandemics, and mandatory reporting requirements. This chapter also identifies new developments, future trends, and international issues related to surveillance in healthcare settings.