This guideline updates and replaces the previous edition of the Centers for Disease Control and Prevention (CDC) “Guideline for Infection Control in Hospital Personnel,” published in 1983. The revised guideline, designed to provide methods for reducing the transmission of infections from patients to healthcare personnel and from personnel to patients, also provides an overview of the evidence for recommendations considered prudent by consensus of the Hospital Infection Control Practices Advisory Committee members. A working draft of this guideline was also reviewed by experts in infection control, occupational health, and infectious diseases; however, all recommendations contained in the guideline may not reflect the opinion of all reviewers.