In this work, Biodiesel was produced from waste cooking oil (WCO) obtained from Mr. Biggs. Since WCO usually comes with a high content of FFA and thus requires an additional acid pre-treatment process to convert the FFA to ester. Two steps (esterification and transesterification) approach was employed to convert the WCO to biodiesel. In the first step, six experimental run was carried out until the % FFA was constant. Meanwhile, the second step required five experimental runs, and the average WCO biodiesel yield (95.06 % w/w) was computed at the following variable conditions, 0.55% KOH, 5:1 Methanol/oil molar ratio, 60 oC reaction temperature and 30 min reaction time. Meanwhile, the produced WCO biodiesel possess some fuel properties which satisfied both ASTME D6751 and EN 1424 standards. The fatty acid profiles of both the WCO and WCO biodiesel revealed that both profiles contained unsaturated fatty acids. Hence, it can be concluded that WCO is a potential raw material for biodiesel production which are biodegradable, economical, environmental friendly and always available. Keywords: Waste cooking oil (WCO), esterification, transesterification, biodiesel, fatty acids profile, physicochemical analysis
