Laboratory workers are at occupational risk of exposure to microrganisms that cause a wide variety of diseases, from inapparent to life-threatening ones. Principal routes of transmission include percutaneous and permucosal inoculation (comprising clinical inapparent cutaneous or mucosal exposure to blood or blood products), inhalation, and ingestion. The appearance of the Acquired Immunodeficiency Syndrome (AIDS) epidemic and the first reports of occupational Human Immunodeficiency Virus (HIV) infections in health care workers resulted in high anxiety among laboratory workers. Indeed, 21% of worldwide documented cases of occupational HIV infection occurred among laboratory workers. Research laboratories pose the highest risk of infection. Safe methods for managing infectious agents ("containment") in the laboratory setting include laboratory practice and technique, safety equipment, and facility design. Infection control in the laboratory setting should take into account adherence to guidelines (biosafety levels), education and training, and the development of safety products designed to reduce the risk of exposure.