Cancer center patients are frequently immune suppressed and are, therefore, at risk for a wide range of opportunistic pathogens in addition to common nosocomial pathogens that are a problem for patients throughout the hospital. A good infection control program is extremely important in this setting to reduce the risks of community- and hospital-acquired infections among patients. In addition to protecting patients, it is also important to protect health care workers, other employees, and visitors. This chapter focuses on general infection control measures, as well as infection control measures specific to patients, health care workers, and visitors in the cancer center setting. In addition, we discuss infection control measures directed at specific nosocomial infections that are of particular risk in this population. Finally, guidelines and examples for starting an infection control program will be given. The role for antimicrobial prophylaxis in infection prevention is discussed in chapter 10.