The reactivity in oxygen and carbon dioxide of chars obtained from the pyrolysis of a refuse-derived fuel (RDF) was investigated. RDF chars were obtained in a fixed-bed pyrolysis reactor at low heating rates (60 degrees C/min) and temperatures between 500 and 800 degrees C. The heterogeneous gasification kinetics of the chars were studied using thermogravimetric methods and were compared to data available in the literature. The RDF chars were found to have a reactivity quite similar to that of chars obtained from municipal solid wastes and wood, but higher than that of graphite of about 5 orders of magnitude in oxygen. Raising the final temperature of the pyrolysis process from 500 to 800 degrees C resulted in the decrease of the H/C ratio and in a significantly lower reactivity in oxygen of the char.