Research indicates that an appropriately designed and maintained upper-room UVGI system may kill or inactivate airborne TB bacteria and increase the protection afforded to healthcare workers while maintaining a safe level of UVGI in the occupied lower portion of the room. The purpose of this document is to examine the different parameters necessary for an effec-tive upper-room UVGI system and to provide guidelines to healthcare managers, facility designers, engineers, and industrial hygienists on the parameters necessary to install and maintain an effective upper-room UVGI system. These guidelines are consistent with previous CDC healthcare guidelines and expand upon them. This document provides an overview of the current knowledge concerning upper-room UVGI systems and research needs. Information from CDC/NIOSH-funded laboratory studies and other relevant studies is combined in this report to provide guide-lines for the installation and use of upper-room UVGI systems. Although other pathogenic microorganisms may be killed or inactivated by upper-room UVGI systems, the guidelines were developed for the installation and use of upper-room UVGI systems capable of killing or inactivating surrogates of mycobacteria.