As an essential thermochemical process, pyrolysis is mainly dependent on temperature. Temperature affects mostly product distribution and composition. In this study, compositional analysis of the products obtained by thermal degradation of biomass at various pyrolysis temperatures (400, 500, 550 and 700 degrees C) with a constant heating rate (300 degrees C min(-1)) was studied. Calorific values of bio-oils were calculated and then compared with raw material. The liquid products obtained at various pyrolysis temperatures were subjected into column chromatography after removal of asphaltenes. Obtained bio-oils were classified as aliphatic, aromatic and polar sub-fractions. Composition of obtained gaseous products as regarding to temperature was determined. Moreover, proximate and ultimate analyses of chars were done. Van Krevelen diagram was demonstrated by plotting H/C and O/C ratios. It was concluded that pyrolysis temperature is effective on composition of products either gas, char or bio-oil. (C) 2006 Elsevier B.V. All rights reserved.