The American Dental Association and several dental specialty organizations have published guidelines that detail requirements for monitoring patients during various levels of sedation and, in some cases, general anesthesia. In general, all these are consistent with those guidelines suggested by the American Society of Anesthesiologists for sedation and analgesia by nonanesthesiologists. It is well accepted that the principal negative impact of sedation and anesthesia is the compromise of respiratory function. While monitoring per se is a technical issue, an appreciation of its purpose and the interpretation of the information provided require an understanding of respiratory anatomy and physiology. The focus of this continuing education article is to address the physiological aspects of respiration and to understand the appropriate use of monitors, including the interpretation of the information they provide.