Simple SummaryMeasurement of body temperature is essential for the study of metabolic changes and inflammation using experimental animals. Although measuring the rectal temperature is often used, this method is not only time-consuming but also stressful for animals. In addition, it is not possible to use this method to make a constant measurement of body temperature. In the current study, we developed an all-in-one packaged telemetry system, which consists of a temperature sensor, transmitter, balun, and a 3-axis accelerometer. The telemetry sensor was easily implanted subcutaneously in rabbits housed in the animal facility while temperature changes were continuously recorded through a personal computer. Our telemetry sensor system may be useful for monitoring body temperature in experimental animals such as rabbits.AbstractContinuous body temperature measurement is an important means of studying inflammation and metabolic changes using experimental animals. Although expensive telemetry equipment for collecting multiple parameters is available for small animals, readily used devices for mediate- or large-sized animals are rather limited. In this study, we developed a new telemetry sensor system that can continuously monitor rabbit body temperature. The telemetry sensor was easily implanted subcutaneously in rabbits housed in the animal facility while temperature changes were continuously recorded by a personal computer. Temperature data obtained by the telemetry was consistent with the rectal temperature measured by a digital device. Analysis of body temperature changes of unstrained rabbits, either under the normal condition or fever induced by endotoxin confirms the reliability and usefulness of this system.