An attempt was made to desulphurise the coal from North Eastern coalfields of Assam in India, characterized by high total concentration of sulphur (2.13%) and high concentration of organic sulphur (1.21%) by using the indigenous fungal culture(Aspergillus sp.) isolated from coal. While using this natural fungal strain, the best results were obtained when desulphurisation was carried out on coal sample of size of -74 mu m, making 2 wt% of extraction mixture for a process duration of 10 days. Final total sulphur content of the desulphurised coal was 0.47%. An elimination, as high as, 70-80% of total sulphur demonstrated the convenience of using the indigenous culture of Aspergillus sp. for desulphurisation. The results advocate an attack of the fungal strain on the organic sulphur component as the sulphur present in Assam coal mainly exist in organic form. In reference to immediate analyses of the coal, it was observed that the ash content was lowered due to acidic conditions imposed by the experimental process. (c) 2005 Elsevier Ltd. All rights reserved.