In this work, the properties (sheet-resistance, temperature coefficient and piezoresistance / gauge factor) and stability of thick-film resistors with low firing temperatures (525...650°C) are studied. To this end, two low-melting lead borosilicate glass composition have been chosen, together with RuO2 as a conductive filler. The effect on the properties and stability of composition and firing temperature is studied. The stability of the materials is quantified during high-temperature storage (annealing) at 250°C. These results show that reasonable resistive and piezoresistive properties, as well as stability, can be obtained even using lower processing temperatures compatible with deposition onto steel, titanium, aluminium and glass substrates.