Bio-oil is a promising alternative source of energy which can be produced from empty fruit bunch (EFB). Bio-oil comprises a mixture of highly oxygenated compounds, carboxylic acids and trace water. Bio-oil can be used as a substitute for conventional fuels after it is upgraded. However, the oil can react through many chemical reactions such as polymerization and lead to an increase in viscosity of bio-oil during storage. Thus, this paper explores the stabilization of empty fruit bunch derived bio-oil. The objective of this project is to select the optimum condition, to study the accelerated aging of bio-oil and the effect of addictive in stabilizing the bio-oil. The bio-oil is produced from the catalytic pyrolysis of EFB. The optimum reaction condition applied is 5 wt of H-Y catalyst at reaction temperature of 500 °C and nitrogen flow rate of 100 ml/min. At this optimum condition, it is able to obtain the maximum bio-oil yield. The method used in this research to improve the stability of the bio-oil is through addition of antioxidants. Four different types of antioxidants which are propyl gallate (PG), tert-Butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA) and calcium chloride salts (CaCl2) are added to the bio-oil separately in the amount of 1,000 ppm. All the test samples are subjected to accelerated aging involving exposure to high temperature of 80 oC for 7 d. The properties of samples which are chosen as the indicator of aging are viscosity, water content and acidity. The effectiveness of antioxidants increase in the following order: CaCl2, BHA, TBHQ and PG. The antioxidants used are able to improve the stability of bio-oil in terms of viscosity and water content during aging. All the antioxidants helped to reduce the acidity of bio-oil except for CaCl2. The results from Gas Chromatography-Mass Spectrometry (GC-MS) analysis showed that the chain reaction of polymerization stopped by phenolics and decrease in carbonyls and ethers can lead to decreased in water content during aging. In addition, molecule decomposing reactions also reduced and resulted in lower acidity. © 2014 Elsevier B.V.