Transmission of M. tuberculosis is a recognized risk to patients and health-care workers (HCWs) in health-care facilities. Transmission is most likely to occur from patients who have unrecognized pulmonary or laryngeal tuberculosis (TB), are not on effective antituberculosis therapy, and have not been placed in isolation. Several recent TB outbreaks in health-care facilities, including outbreaks of multidrug-resistant TB (MDR-TB), have heightened concern about nosocomial transmission. Patients who have MDR-TB can remain infectious for prolonged periods, which increases the risk for transmission. Transmission to human immunodeficiency virus (HIV)–infected persons is of particular concern because they are at high risk for developing active TB if they become infected. Although completely eliminating the risk for transmission of M. tuberculosis in all health-care facilities may not be possible, adherence to certain fundamental TB infection control measures should reduce the risk to persons in those settings.