Abstract : Thermal degradation of sugar cane bagasse has been studied between 200 and 800°C under a nitrogen gas flow. Different experimental parameters of the pyrolysis have been investigated , including holding temperature. time duration of pyrolysis, and heating rate. The solid residues obtained were then analyzed by classical elemental analysis and Fourier transform infrared (FTIR) spectroscopy. The most important structure modifications appeared between 300 and 400°C. and they are characterized by the decrease of intensities of CO and C=C bands and the formation of alkyl bands. The thermal degradation of bagasse is marked by dehydration and the formation of CO and CO, molecules. The carbonization is characterized by the disappearance of chemical bonds and the formation of low molecular weight compounds leading to a char consisting essentially of carbon, hydrogen and mineral oxides.