The thermal decomposition of sugarcane bagasse and cassava bagasse was investigated by the use of the non-isothermal thermogravimetric technique. The experiments were performed with the following heating rates: 5, 10, 15, 20 and 30 °C min−1. The kinetic parameters of thermal decomposition were estimated by the Flynn–Wall–Ozawa and the Kissinger methods. The results obtained for activation energy by the Flynn–Wall–Ozawa method were in the range of 126.62–148.80 kJ mol−1 for the sugarcane bagasse and 157.64–227.74 kJ mol−1 for the cassava bagasse, whereas the Kissinger method resulted in 124.54 kJ mol−1 for the sugarcane bagasse and 144.31 kJ mol−1 for the cassava bagasse. The pyrolysis of sugarcane bagasse occurred in the temperature range 270–480 °C with average efficiency of 85.23 %, whereas the pyrolysis of cassava bagasse occurred in the range 270–540 °C with average efficiency of 98.85 %. The experimental result for the high heating value was 16.103 MJ kg−1 for sugarcane bagasse and 15.274 MJ kg−1 for cassava bagasse, which means that these materials are suitable for use as alternative fuels. © 2016 Akadémiai Kiadó, Budapest, Hungary125 437445