The risk of health-care workers to become infected with HIV during professional activities is low. Prevention of exposures by obeying appropriate precautions is the most important means to lower this risk further. During the last few years it has become more and more likely that an immediate antiretroviral postexposure prophylaxis can prevent at least 80% of possible infections. Thus, each exposure to HIV-positive blood should be considered an acute medical emergency. Immediate counseling by qualified experts and possibilities to start postexposure prophylaxis as soon as possible should be available in all medical settings.