This paper investigates the chemical elemental characteristics of 63 samples of biomass including agricultural biomass such as rice straw, wheat straw, corn straw, cotton straw and forestry biomass such as birch, spruce, willow, etc. in China. Twenty one different biomass groups are distinguished as reference fuels in China. The elemental characteristics of bituminous coal are also presented for comparison. (C) 2004 Elsevier Ltd. All rights reserved.