Biodiesel is an alternative fuel for engine and other appliances that is obtained by transesterifying vegetable oils or other materials largely comprised of triacylglycerols with monohydric alcohols to give the corresponding mono-alkyl esters. The quality of feedstocks for the biodiesel production dictates the method of its production and quality. Based on the initial amount of minor components in feedstocks, a process comparison of acid pre-treatment and caustic pretreatment of feedstock for alkali transesterification was done. Acid pre-treatment was carried out with 0.60 w/w methanol-to-oil ratios in the presence of 2% w/w H 2 SO 4 as an acid catalyst in 2 h reaction at 60 °C. In caustic pretreatment process, the same amount of oil was neutralized with the required amount of sodium hydroxide based on the initial amount of free fatty acid and gums in the oil. The acid pretreatment process gives a 4% loss in feedstock compared to 20% from the neutralization process. The yields 96% and 94% of biodiesel from acid pretreated and caustic pretreatment feedstock were obtained respectively. The oxidation stabilities of biodiesel from acid pretreatment and neutralized feedstock were 1.12h and 3h respectively. The biodiesel from acid pretreatment oil could not pass the ASTM standard.