The main objective of this work is to investigate the chemical composition of the volatile compounds produced during the pyrolysis of sugar cane straw (SCS). The pyrolysis was conducted in a vertical furnace using a quartz reactor at a temperature of 700 degrees C (7 g of SCS, heating rate of 60 degrees C/mm flux of 1 mL min(-1) of N-2 and 5 min of hold time at the final temperature). Pyrolysis products (solid residue and bio-oil) were analyzed. The original biomass and the residual solid phase were characterized by Thermogravimetric Analysis (TGA) and Infrared Spectroscopy (FTIR). The biomass showed a TGA profile similar to cellulose and, according to FTIR analysis, it was rich in oxygenated compounds. The FTIR analysis of solid residue indicated that it was composed mainly by silica. Comprehensive two dimensional gas chromatography with time of flight mass spectrometry detector (GC x GC/TOFMS) was applied in the identification and semi-quantification of main compounds in bio-oil, allowing the identification of 123 compounds, mainly oxygenated (acids, ethers, aldehydes, ketones and phenols) with a predominance of furfural and hexenoic acid. The GC x GC/TOFMS allowed a group type classification of the compounds and a spatial organization that facilitated the identification of the main compounds in the 2D diagram. (C) 2012 Elsevier B.V. All rights reserved.