Biomass gasification trials have been performed by using a fluidized bed made of used and fresh olivine particles, and Catalytic and Non-Catalytic filters of new type, placed in the freeboard of the gasifier. All tests were performed continuously at temperature of 800 °C in presence of steam. The optimum result has been obtained with the simultaneous presence into the gasifier of the used olivine particles and the Catalytic filter. When the Non-Catalytic filter is placed into the gasifier, in presence of used olivine as a bed inventory, the H2 yield increases steadily during the four hours of gasification time, whereas in presence of Catalytic filter the yield of H2 reaches the steady state value after only one hour of gasification time. The presence of a layer of char particles on the candle surface has a positive effect on tar, methane and ammonia conversion. The use of Filters inside the gasifier permits to improve the contact between the char particles and the mixture of gas and vapours produced during the biomass devolatilization process, as a result a cleaner gas is obtained, making this technological solution particularly attractive.