The production of biodiesel derived from olive acid oil in supercritical ethanol was investigated by using a tubular reactor of 45 ml in a bench-scale. Experiments were performed based on experimental design, and operating conditions such as temperature (280-360°C), pressure (100-180 bar), volumetric ratio of ethanol to OAO (1:1-1:2), and flow rate of the mixture (0.3-0.9 ml/min) were selected as parameters to evaluate their effects on ester conversion. Samples collected were purified with magnesol after removing of ethanol by vacuum distillation. Ethyl ester contents were determined by gas chromatography analysis. Subsequently, accelerated oxidation stability tests of biodiesel samples were studied at a temperature of 110°C by using the Rancimat 743, and following the European standard EN 14214