Biomaterials can be converted into solid, liquid and gaseous fuels through thermochemical or biochemical conversion processes. Thermochemical conversion of granular biomaterials is difficult because of its physical nature and one of the suitable processes is fluidized bed gasification. In this study, coir pith, rice husk and saw dust were selected and synthetic gas was generated using a fluidized bed gasifier. Gas compositions of product gas were analyzed and the percentage of carbon monoxide and carbon dioxide was in the range of 8.24-19.55 and 10.21-17.14, respectively. The effect of equivalence ratio (0.3, 0.4 and 0.5) and reaction time (at 10 min interval) on gas constituents was studied. The gas yield for coir pith, rice husk and sawdust were found to be in the range of 1.98-3.24, 1.79-2.81 and 2.18-3.70 Nm(3) kg(-1), respectively. Models were developed to study the influence of biomaterial properties and operating conditions on molar concentration of gas constituents and energy output. (C) 2010 Elsevier Ltd. All rights reserved.