In this paper we present the tests of high temperatures resistances of glass fibre cement plates. The aim of the research was to determine the values of tensile strength in bending for samples subjected to annealing at temperatures 200, 300, 400 and 500 °C in endurance at the highest temperature level for 24 hours. The bending strength was performed according to the norm EN 1170-4. The thermal dilatometric analysis was performed on the plates in the temperatures till 540 °C