The goal of instrument processing is to protect patients by preventing cross-contamination from instruments. The processing involves a series of sequential steps aimed at removing and killing microbes on contaminated instruments and maintaining those instruments in an aseptic state until they are reused. These steps must be conducted carefully to assure success and to reduce chances of disease spread or physical injury to those handling the contaminated instruments. Presoaking begins the cleaning process and facilitates terminal cleaning by ultrasonic or manual scrubbing. If instruments are not properly cleaned, subsequent sterilization may be jeopardized by insulation of blood- or saliva-coated microbes from the sterilizing agent. Items that would be destroyed by heat should be cleaned and sterilized in a properly prepared glutaraldehyde solution. Cleaned instruments must be packaged prior to heat sterilization to protect them from recontamination after sterilization and before reuse. Sterilization of cleaned, packaged instruments in steam, chemical vapor, or dry heat sterilizers must involve proper loading, processing, drying, and cooling. Routine use of spore tests and chemical indicators will provide quality assessment of packaging procedures and operation of the sterilizer, as well as assist in identifying processed packages during distribution. Using the results of sterilization monitoring to adjust procedures as a means of assuring sterilization provides quality assurance to the office staff and to the patients that the instruments have been properly processed. Carefully handling storage and distribution of the sterilized instrument packs or trays reduces the chances for recontamination until the instruments are reused. Instrument processing is a major part of the office infection control program. It must be performed in a controlled manner with proper monitoring to achieve the desired outcome of patient protection.