The effects of process parameters and Ni/Mo atomic ratio on catalytic hydrocracking of soybean oil were investigated using the carbide or nitride forms of Ni/Mo supported on ZSM-5 catalysts. Essentially, a complete conversion of the triglycerides was observed at 650 psi and 360-450 degrees C. A low reaction temperature (360 degrees C) resulted in a significant change in selectivity toward hydrocarbon fuels. After a 4 day reaction, only 3-5% of hydrocarbon fuels were produced together with considerable amount of carboxyl acids (very high acid number up to 140 mg KOH/g). The gaseous phase products at 450 degrees C indicated that the nitride catalyst favors a methanation reaction more than the carbide catalyst by producing a larger amount of methane in the gaseous product. At a lower liquid hourly space velocity (1 h(-1)), about 70 wt % of gasoline to diesel range hydrocarbons were obtained in the organic liquid products compared to 25 wt % at 2 and 3 h(-1). Increasing the Ni content in the catalyst improves the hydrogenation ability of the catalyst, since Ni is known to activate hydrogen and transfer protons and electrons to molybdenum. A larger fraction of gasoline was produced in the organic liquid product while similar jet and diesel range hydrocarbons were obtained by increasing the Ni/Mo atomic ratio from 0 to 1.5. However, a decreased fraction of the organic product was generated with an increasing amount of Ni content in the catalyst. Overall, the highest yield of hydrocarbon fuels (about 50 wt %) was obtained when the Ni/Mo molar ratio was 0.5.