Apricot stones steam pyrolysis tar and mixtures with petroleum pitch were modified by sulfuric acid and heat treatment at various temperatures for the purpose of obtaining a raw material for the production of carbon-related materials. The products obtained were characterized by elemental analysis, total carbon contents. FTIR spectroscopic analysis. H-1 and C-13 NMR spectroscopic analyses. softening point measurement, and oxygen functional group content. During the acid and heat treatment. the reactions of polycondensation and polymerization occur. The heat-treatment modification of the pitches decreases the oxygen-containing groups and sulfur content and increases the content of aromatic structures. Chemical transformations and the removal of light components increase the softening point of the pitches. The results show that apricot stones tar with some additional modifications can be used as a raw material for the production of advanced carbon materials. (C) 2002 Elsevier Science B.V. All rights reserved.