Huge quantities of waste cooking oils are produced all over the world every day, especially in the developed countries with 0.5 million ton per year waste cooking oil are being generated in Malaysia alone. Such large amount of waste cooking oil production can create disposal problems and contamination to water and land resources if not disposed properly. The use of waste cooking oil as feedstock for biodiesel production will not only avoid the competition of the same oil resources for food and fuel but will also overcome the waste cooking oil disposal problems. However, waste cooking oil has high acid value, thus would require the oil to undergo esterification with an acid catalyst prior to transesterification with a base catalyst. Therefore, in this study, bifunctional catalyst supports were developed for one-step esterification-transesterification of waste cooking oil by varying the CeO2loading on γ-Al2O3. The bifunctional supports were then impregnated with 5 wt Mo and characterized using N2adsorption-desorption isotherm to determine the surface area of the catalysts while temperature programmed desorption with NH3and CO2as adsorbents were used to determine the acidity and basicity of the catalysts. Results show that the γ-Al2O3-CeO2supported Mo catalysts are active for the one-step esterification-transesterification of waste cooking oil to produce biodiesel with the Mo/γ-Al2O3-20 wt CeO2as the most active catalyst. Optimization of process parameters for the production of biodiesel from waste cooking oil in the presence of this catalyst show that 81.1 biodiesel yield was produced at 110oC with catalyst loading of 7 wt, agitation speed of 600 rpm, methanol to oil ratio of 30:1 and reaction period of 270 minutes. © 2015, Malaysian Society of Analytical Sciences. All rights reserved.