The developed two-phase air-steam gasification model (Biomass Bioenergy, xxxxx) was validated using the experimental results obtained from a dual distributor fluidized bed reactor. The reactor was operated on wheat straw at various fluidization velocities, steam flow rates and biomass to steam ratios. A good agreement between the model predictions and experimental data was obtained under all operating conditions studied. The model predicted the temperatures of the bubble, emulsion and solid phases, the mole fractions of methane, hydrogen, carbon monoxide, carbon dioxide and nitrogen, and the higher heating value of the producer gas with high accuracy (R-2 = 0.88-0.98). The correlation coefficient (R2) for the gas production was somewhat lower (0.75), which could be attributed to the assumption that the gases behaved ideally.