Because of the tremendous increase in corn ethanol production, the need to utilize the distillers' grains byproduct is increasing. Biomass gasification is a thermochemical process for converting solid fuel to gaseous fuel. In this study, gasification of distillers grains was performed on a bench-scale fluidized-bed gasifier with steam and air as fluidizing and oxidizing agents. The goal was to investigate the effects of steam to biomass ratio, air to biomass ratio and furnace temperature on gas composition and energy conversion efficiency of the product gas. The gasification temperature was the most influential factor affecting energy efficiency and hydrogen content of the product gas. Increasing the temperature resulted in increases in efficiency and hydrogen content. The efficiency and methane content increased and decreased, respectively after reaching a maximum with an increase in steam to biomass ratio. The equivalence ratio increased the efficiency but decreased the hydrogen content and had a minimal effect on the methane content.