Oxidative pyrolysis is an effective way for the autothermal operation of staged gasification and carbonization processes. The airn of this work was to investigate the influence of biomass properties on yields, and composition of the products: char, condensates and permanent gases. Oxidative pyrolysis of three biomasses -Pine, Miscanthus and Wheat straw- were performed in a fixed bed reactor. The mass and energy distribution in the products were established and compared. Char yields were measured to 19%, 25% and 27% for Pine, Miscanthus and Wheat straw pellets, respectively. Temperatures along the bed were measured to be lower than 750°C. The ER was found to be in range of 11 to 1 4% for the three biomass cases, and about 79% of the energy content in the biomass is converted into the pyrolysis products. The results highlight the important role of biomass properties, especially ash content, on the oxidative pyrolysis.