In this study, effects of total mineral matter content and of elements Ca, Mg, Na, K, Si and Al on the combustion reactivity of 25 lignite samples, originating from different areas of Turkey, was investigated. Non-isothermal thermogravimetry, where the sample was heated in air and the temperature of which increased at a linear rate of 40 K min(-1) to 1273 K, has been used to investigate the combustion reactivities of the lignite samples. The calculated combustion activation energy values were related to the mineral impurities and definite correlations were observed.