Pine sawdust catalytic pyrolysis has been studied in a fluidized bed at temperatures of 650 and 700 degrees C. The experimental work was carried out in a bench-scale plant based on Waterloo Fast Pyrolysis Process (WFPP) technology. The Ni-Al catalyst used was prepared by coprecipitation with a molar ratio 1:2 (Ni-Al) and calcined at 750 degrees C for 3 h. The catalyst was not reduced prior to the biomass reaction. The influence of the catalyst weight/biomass flow rate ratio (W/ mb) on the product distribution and on the quality of the gas product obtained was analyzed. An increase of the W/mb ratio increases the total gas yield and diminishes the liquid yield : When the W/mb ratio increases, H-2 and CO yields increase while CO2, CH4, and C-2 yields decrease. For W/mb ratios greater than or equal to 0.4 h, no significant modifications are observed on the initial yields of different gases, and it is confirmed that under these conditions the initial gas composition is similar to that for thermodynamic equilibrium. For W/mb ratios < 0.4 h, a simple first-order kinetic equation has been suggested for H-2 and CO formation.