The effect of calcination conditions on the physical properties of calcines produced from natural Turkish limestones and dolomites was investigated. Calcination experiments were conducted in a tube furnace at temperatures of 1073, 1123, 1173, 1273, mid 1373 K. Two different gaseous atmospheres were employed, namely, dry air (100 vol%) and a mixture consisting of CO2 (15 vol%) and dry air (85 vol%). The physical properties, which involve bulk density (g/cm(3)), total pore volume (cm(3)/g), and the pore size distribution of the calcines prepared undet different conditions, were determined using a mercury porosimeter. It was found that the physical properties of calcines were dramatically affected by the calcination conditions. At high calcination temperatures, because of sintering and shrinking effects, a decrease in porosity, an increase in bulk density and average pore radius were observed. In addition, the calcines prepared in a mixed atmosphere of dry air and carbon dioxide had larger pore sizes than those of calcines prepared in an atmosphere of dry air.