Gas chromatography-mass spectrometry (GC-MS) method was applied for investigation of the extracts obtained from three pairs of Donets bituminous coals (76-79% of C-dat) of similar rank but differing in sulphur content. The elemental characteristic of the coals and hydrocarbon composition of their extracts reflect the differences in the environments Of Sulphur coals formation and differences in their structure, The thermal and natural coalification pathways of low- and high-sulphur coals formed under low-reduced and reduced conditions during early diagenesis were determined. (C) 2002 Elsevier Science B.V. All rights reserved.