Abstract: A temperature sensor for measuring and/or monitoring the temperature of a medium flowing in a flow conduit of an internal combustion engine. The sensor has a one-piece plastic body with a sensor and plug part, a resistor element, connecting plug tongues, and a housing that receives the sensor part. In order to reduce production and installation costs and to attain other advantages as well, the housing is of temperature-resistant plastic that absorbs little moisture, sprayed directly onto the sensor part. For sealingly and securing the housing in a receiving bore in the wall of the flow conduit, a radially protruding annular bead is injection molded to the housing, and a sealing ring is plastic between the plug part and the annular bead.