Catalytic fast pyrolysis (CFP) conversions of sugarcane bagasse (pretreated and untreated, or "raw") over HZSM-5 zeolite catalyst were conducted in a fluidized-bed reactor to compare the hydrocarbons yields and selectivities of pretreated and raw biomass materials in order to determine the effect of inorganic matter on the aromatics and olefins yields. The effects of reaction temperature and sweeping gas flow rate (SGFR) on aromatics and olefins yields and selectivities were studied. The results showed that a maximum aromatics yield of 12.41% carbon was obtained during CFP of pretreated sugarcane bagasse at an optimum gas flow rate of 2.5 L min(-1) and temperature of 500 degrees C. The highest olefins yield was 10.89% carbon under the same CFP conditions. Benzene and ethylene were the dominant compounds in the aromatics and olefins, respectively. The highest selectivities to benzene and ethylene were 46.44% and 45.45% carbon, respectively. Slightly lower aromatics and olefins yields of 11.77% and 9.9%, respectively, were obtained from CFP of untreated biomass. In the final step, the yields of aromatics and olefins for the raw and treated sugarcane bagasse were compared, and in addition the yields and selectivities at optimum conditions were compared. The results suggest that inorganic matter has an inhibiting effect on hydrocarbons production and also causes catalyst deactivation by blocking the catalyst pores. It is evident that removal of inorganic matter would increase both liquid and hydrocarbons yields during CFP over HZSM-5. Hydrocarbons yields and selectivities were found to depend not only on temperature and SGFR but also on the severity of the treatment process.