In this research, combustion properties and kinetics of different biomass samples known as poplar wood, hazelnut shell and wheat bran were studied using thermogravimetry-mass spectrometer. Experiments were performed at three different heating rates (10, 20 and 30 A degrees C min(-1)) under air atmosphere. The reaction regions, peak and burnout temperatures, mass loss, maximum mass loss rate and residue of the biomass samples were determined. It was observed that all the biomass samples studied show similar combustion characteristics. This study was also focused on the main volatile products (H-2, O, CO and CO2, etc.) of biomass combustion on the basis of their relative intensities across the temperature range 150-750 A degrees C and on their relevancy, respectively. Activation energy and Arrhenius constant of the biomass samples were calculated using two different iso-conversional methods, known as Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose. It was observed that the activation energy values were in the range of 66.80-68.56 kJ mol(-1) for poplar wood, 83.73-93.25 kJ mol(-1) for hazelnut shell and 162.17-167.4 kJ mol(-1) for wheat bran, respectively. The biomass reactivity is directly related to the light volatile content, whereas combustion of fixed carbon affected the energy release.