The desulphurization of four samples of Central Anatolian lignites by treatment with aqueous NaOH was examined. NaOH concentration and temperature were the significant parameters but the extraction time had only a slight effect. Organic sulphur was not removed from three of the samples but in the other lignite 12.5 wt% of the organic sulphur was removed by treatment at 70 °C for 8 h with 20 wt/v% NaOH solution. Total sulphur contents were considerably reduced by aqueous NaOH treatment but one high-sulphur lignite was found to be more resistant to sulphur removal than the others. This lignite was treated with molten caustic at 300 °C and 450 °C with the result that the total sulphur and ash contents were reduced by 47-83 wt% and 77-91 wt% respectively. © 1988.