In this study, combustion and co-combustion characteristics of three biomass fuels and three Turkish lignite coals were investigated by using a thermo gravimetric analyzer. There are just a few studies investigating the co-combustion characteristics of coal and biomass, and the synergistic effect of their various combinations on the peak temperatures and burnout times. Results of this study have shown that low rank coals can be burned with biomass very beneficially. As the VM content of the coal increases, the ignition temperature decreases and the maximum combustion rate is reached at lower temperatures. About 80-90% of the fuel is combusted as the combustion of volatile matter. As the biomass content of the fuel mixture increases, the ignition temperatures of the mixtures are found to be very close to that of the biomass. Therefore, it can be said that biomass in the mixture starts to burn first and then coal follows. (C) 2010 Elsevier B.V. All rights reserved.