Lignite was briquetted with oat straw and cellulose fibers (20-50% by mass) in a cylindrical mold and in a roll press to det. the pressure-d. relationships. The briquettes were studied for compression and impact strengths and for water resistance. Effects of the biomass-to-lignite ratio and applied pressure on the strength of the briquettes were examd. Impact resistance index of the briquettes showed a max. at 30% content of the biomass. Both compressive strength and water resistance decreased with increasing biomass content.