The present study investigates the effect of several experimental iron-based granules on biomass tar decomposition. The iron-based materials were provided by Hoganas AB and were all in their metallic state when they were applied in a secondary catalytic reactor. Bark-free birch was employed as fuel in an atmospheric fluidised bed reactor, and the tar concentration and gas composition in the producer gas were measured before and after the catalytic bed. The results demonstrate a clear tar reduction capacity for all the tested iron-based materials. (C) 2010 Elsevier B.V. All rights reserved.