Abstract. Available epidemiological data show that the risk of viral transmission from an infected healthcare worker to a patient is extremely low for HIV and HCV, and higher for HBV. The majority of published cases involved healthcare workers infected with HBV, most of whom were HBeAg carriers. Since the early 1990s, cases of healthcare worker-to-patient transmission of HIV and HCV have also been reported. The risk of transmission exists almost exclusively during surgical, obstetric, and dental procedures but varies depending on the type of procedure performed and the infectivity of the healthcare worker. Apart from hepatitis B vaccination, which is essential, the prevention of healthcare-associated transmission relies on preventing blood-exposure incidents among healthcare workers and, therefore, on the application of standard precautions and the development of appropriate surgical practices. (R.A.)