In the sintering of iron ores, the chemical composition and the physical properties of coke breeze has a significant effect on the sinter process and the sinter quality. This paper is focused on the influence of coke breeze from different deposits and coking plants respectively, on the sinter process in particular on the off gas composition and the sinter quality. Laboratory-scale sinter feed mixtures with various sorts of coke breeze are produced, whereby the particle size distribution of the investigated coke breeze is constant as well as the coke breeze content with respect to the fixed carbon content. The small scale sinter experiments are performed in cylindrical packings of sinter mix. During the sintering the emissions of CO, CO2, NOx and SO2 in the off gas are monitored, as well as specific sintering parameters e.g. the sinter yield and strength. The results of the off-gas analysis are compared with the chemical elemental analysis of the coke breeze. The investigations demonstrate that a high carbon content of the coke breeze leads to a higher pressure loss across the sinter bed, thus to a shorter sintering time and correspondingly to higher productivity. Changes in the nitrogen concentration in the coke breeze cause significant NOx variations in the off gas. As expected, the total sulfur in the off gas cannot be entirely attributed to the coke breeze. The findings obtained on a laboratory scale enable a coke breeze characterization close to an industrial sinter belt, demonstrating the expected process parameters.