Infection control is the discipline responsible for preventing nosocomial infections. There has been an increasing focus on prevention rather than control of hospital-acquired infections. Individuals working in infection control have seen their titles change from infection control practitioner to infection control professional and most recently to infection preventionist (IP), emphasizing their critical role in protecting patients. The responsibilities of IPs span multiple disciplines including medicine, surgery, nursing, occupational health, microbiology, pharmacy, sterilization and disinfection, emergency medicine, and information technology. This article discusses the structure and responsibilities of an infection control program and the regulatory pressures and opportunities the program faces.