Synthesis of biodiesel via acid catalyzed reaction using trap grease as feedstock was carried out using the ex- perimental setup as shown in Figure 1. The experimental procedure as described by Zhang and Jiang (2008) was employed with a slight modification in the phase separation technique. The 100 g air-dried trap grease was poured into a three-neck round bottom flask and pre-heated to 60°C using a water bath with temperature controller (Fisher Scientific, Model ISOTEMP 228). The solution of H2SO4 in methanol was also preheated and added to the flask. The mixture was stirred at the same speed of 600 rpm for all test runs using a Sted fast™ stirrer (Fisher Scientific, Model SL2400). Heating and stirring were stopped after the reaction has reached the preset reaction time. After the reaction, the solution and solid phase of remaining trap grease was separated by centrifuga- tion with a centrifuge (Sanyo, Model Centaur2) operated at 3,000 g for 10 min. The recovered solid phase was then ana- lyzed for its acid value. The supernatant was decanted into a separating funnel and was washed four times using hot water (80°C) to remove the remaining catalyst. Excess methanol and water were removed by evaporation at 110°C. The percent- age of purified ester phase was determined using 1H Nuclear Magnetic Resonance spectroscopy (1H-NMR).