Abstract: This invention relates to gases distribution systems and in particular, to temperature sensors. The sensor of the present invention is configured to determine the temperature of a flow of respiratory gases and comprises a sensor housing (36) configured for positioning proximate to a flow of gases and a temperature transducer (31) housed within the sensor housing (36). The sensor housing (36) provides a substantial pathogen barrier between the flow of gases and the temperature transducer (31), but permits the temperature transducer to provide a substantial indication of the temperature of the flow of gases. In particular, the temperature of the gases is remotely sensed via a conductive path (38) through the wall of the breathing circuit (14). This conductive path (38), integral to the breathing circuit (14), could then be disposed of or reused after suitable sterilisation.