The oxygenated functions issued from the oxidative thermal treatment of mesocarbon microbeads (MCMB) at 320°C were investigated by thermogravimetric (TG) and Fourier transform infrared spectroscopic (FT-IR) techniques (especially in diffuse reflectance DRIFT mode). Based on the curve fitted spectra in carbonyl frequencies, the semi-quantitative FT-IR analysis gives some evidence on the reactions kinetic and mechanism. The direct relation between TGA and FT-IR results is illustrated.Les groupements fonctionnels oxygenes produits dans le traitement thermique oxydant a 320 °C de microbilles de carbone (MCMB) ont ete etudies par analyse thermogravimetrique (ATG) et spectroscopie infrarouge a transformee de Fourier (IRTF). L'analyse semi-quantitative des spectres IR, apres traitement mathematique, permet de suivre la cinetique de l'oxydation et donne des renseignements sur les mecanismes.