The examinations of the extent of sinter reduction were carried out in simulated conditions of a blast- furnace at the temperatures of950 and I 100 °C. Two cokes with different reactivity were applied. An analysis was carried out to determine whether it was possible for the CO2, formed in situ as a result of sinter reduction by means of CO, to react with coke. It was shown, that at the temperature of 950 °C the reaction of CO2 with coke did not occur. The reduction of iron - bearing materials at that temperature occurs by way of indirect reduction without the participation of coke carbon. With the growth of temperature up to about 1100 °C the reaction CO2+ C = 2CO becomes an important process influencing the course of the reduction and coke consumption. The effect of coke reactivity on the course of direct reduction was also analysed. Increasing of coke reactivity results an increase in the amount of coke for the reaction CO2+ C= 2CO. The type of packing of the reduced sinter and coke influences the rate of the material reduction.