Study of biodiesel production through in situ ethanolysis of Jatropha curcas was conducted by investigating the effect of reaction time, reaction temperature, type of catalysts and their concentration. Base catalysts such as sodium hydroxide, potassium hydroxide and sodium methoxide were used to enhance the reaction which was carried out in a batch system. The fatty acid ethyl ester content in the reaction mixture was determined by gas chromatography based on ASTM D 6584. The highest yield of the ethyl ester achieved was 99.98 under the optimum conditions: 2.0 wt. of CH 3ONa, reaction temperature of 30 °C and 2 h of reaction time. The biodiesel properties for instance flash point, viscosity, acid value and total glycerine meet the specification of the ASTM D 6751-07a. © 2011 Elsevier Ltd. All rights reserved.