Abstract: The resistance temperature detector (RTD) includes a substrate of refractory dielectric material having two or more holes bored through it. A plug of electrically conductive material is fixed within each hole in proximity to one end surface of the substrate, with the plug surface preferably having a concave meniscus shape and consisting of a metal alloy such as Ti-Ni. Lead wires, such as Ni wires, are located in the holes and are connected to the plugs through the other end surface. A film of temperature dependent resistance material is deposited on the one end surface of the substrate and is connected to the two plugs. The film may consist of a thin sensing film of metal such as platinum or of a semiconductor material, deposited in a selected pattern on the substrate and in direct contact with the plugs, or the sensing film may be deposited so as to connect pads of electrical conducting material which are deposited to cover at least a portion of the plugs.