Under the influence of fire and other high heat sources, a number of changes occur in natural stones. These changes vary according to the values of the temperature exposure. Therefore, this study aims to understand the effect of heat in a fire and high temperatures on some properties of limestone and marble, as they are widely used natural building stones. For this purpose, eight natural stones (four limestone and four marble) of different origins and textural characteristics were exposed to 200, 400, 600, 800 and 1000 degrees C temperature in the oven. After each exposure, the rock properties were determined and compared with the properties at room temperature. Discoloration and whiteness, polish reception, daily physical change, variation of pH and temperature of the cooling solution were taken into account in the comparison. As a result of this study, the positive and negative aspects of the property changes that occur in natural stones which are exposed to different temperatures are discussed. (C) 2012 Elsevier Ltd. All rights reserved.