A sensitivity analysis was performed on the two phase biomass gasification model developed by Sadaka et al. (Biomass Bioenergy) to test its response to variations in three operating parameters (fluidization velocity. steam flow rate and biomass to steam ratio). The model performance criteria included bed temperature, gas compositions, higher heating value and gas production rate. The results showed that the model was sensitive to changes in all operating parameters. The temperatures of the reactor were more influenced by changes in the steam flow rate than those of fluidization velocity and biomass to steam ratio. The steam flow rate has the most effect on the mole fractions of CH4, and CO2 followed by the biomass to steam ratio and then the fluidization velocity, In the case of H-2, and CO the biomass to steam ratio has the most effect on their mole fractions followed by the steam flow rate and then fluidization velocity. The fluidization velocity has the most effect on the mole fraction of N-2. The biomass to steam ratio has the most effect on the gas higher heating value and the gas production rate.