The anesthesia workstation is defined as a system for the administration of anesthesia to patients consisting of the gas delivery system, breathing system, anesthetic gas scavenging system, anesthetic vapor delivery system, anesthesia ventilator, and associated monitoring and protection devices. This chapter describes in detail the basic components of the gas delivery system, otherwise known as the anesthesia machine. It then provides an overview of the anesthesia workstations currently approved for use in the United States.