The objective of the paper was application of bacterial leaching on 2 brown coal samples from bore S 187 (CV) from locality Mine CSA Most. Based on the results of bacterial leaching and petrologic analyses of the given samples, it is possible to state that the individual samples are very similar, they contain significant shares of clay materials and pyrite is predominantly represented in a framboidal form, which intergrowths into a massive form. Applying bacterial leaching it is possible to remove from 32 to 38% of total sulphur and from 30 to 32% of pyritic sulphur from the coal; better results are obtained eliminating sulphate sulphur, i.e. up to 50% desulphurization.