The effects of lignite type and lignite particle size on the rate of sulphur removal were studied. Biodesulphurization experiments were carried out with Mengen, Elbistan, Tuncbilek and Gediz lignites at the optimum growth conditions of Rhodococcus rhodochrous. The highest decreases in the total (25.3%) and organic sulphur contents (21.4%) were obtained with Giediz and Mengen lignites, respectively. Furthermore, increased desulphurization rates have been observed with smaller particle sizes. Reduction in particle size from 390 to 63 mu m resulted in an increase in total sulphur and organic sulphur removal rates by factors of 2.8 and 19, respectively.