Intoduction: The phrase "Monitored Anesthesia Care" refers to instances in which an anesthesiologist has been called upon to provide specific anesthesia services to a particular patient understanding a planned procedure, in connection with which a patient receives local anesthesia. Monitored anesthesia care is being increasingly used in the 1990s for a wide variety of diagnostic and therapeutic procedure. The primary objective in providing monitored anesthesia care is to ensure patient comfort and safety. METHOD: We classified patients in three groups by premedication and oxygen administration, no premedication and no oxygen administration (group A), premedication and oxygen administration (group B), premedication and no oxygen administration (group C), measured vital signs and SpO2 (peripheral oxygen saturation) from just before operation, and checked the satisfaction score of surgeon and patients. RESULT: SpO2 and satisfaction score of surgeon and patients are the best at premedication and oxygen administration group. CONCLUSION: Monitored anesthesia is assumed to give more comfort and safety to patients than local anesthesia alone.