Sugar cane bagasse is one of the most viable biomass fuels in Thailand. However, because of high moisture content in the fuel (of 45-55%), combustion of "as-received" bagasse is rather ineffective and unstable process. In this experimental work, the bagasse was preliminarily dried before conducting combustion tests on a fluidized bed combustor with a conical bed. Silica sand was used as the inert bed material for ensuring sustainable fuel ignition and combustion in this reactor. Effects of operating variables (fuel feed rate and excess air) as well as static bed height on the axial temperature and gas concentration profiles (for O-2, CO2, CO and NOx) in the combustor were investigated. For estimating the environmental impact by this bagasse-fuelled system, CO and NOx emissions from the combustor were quantified. The combustion efficiency was found to be in the range of 96 to 99.7% for firing the pre-dried sugar cane bagasse in wide ranges of the operating variables. (c) 2004 Elsevier B.V. All rights reserved.