Fuel pellets with a sintering point of 59 (Roga Index, RI), consisting of coal, biomass and binder in a mass ratio of 90:6:4 dry matter, were oxidized with air under lab. conditions at 150, 200 and 300 degrees C when exposed to oxidizing agent for 5, 15, 30 and 60 min. The sinterability of the pellets decreased with the increase of temp. and the extension of the process time. The RI below 18 was obtained for the samples oxidized at 150 degrees C for 60 min and at 200 and 300 degrees C for at least 15 min.