Respiratory protection is used as a method of protecting individuals from inhaling harmful airborne contaminants and in some cases to supply them with breathable air in oxygen-deficient environments. This article focuses on the use and types of personal respiratory protection (respirators) worn by individuals at workplaces where airborne hazardous contaminants may exist. Respirators are increasingly also being used in nonindustrial settings such as health care facilities, as concerns regarding infectious epidemics and terrorist threats grow. Pulmonologists and other clinicians should understand fundamental issues regarding respiratory protection against airborne contaminants and the use of respirators.