A technique to produce biodiesel from crude Jatropha curcas seed oil (CJCO) having high free fatty acids (15%FFA) has been developed. The high FFA level of JCJO was reduced to less than 1% by a two-step pretreatment process. The first step was carried out with 0.60 w/w methanol-to-oil ratio in the presence of 1% w/w H2SO4 as an acid catalyst in 1-h reaction at 50 degrees C. After the reaction, the mixture was allowed to settle for 2 h and the methanol-water mixture separated at the top layer was removed. The second step was transesterified using 0.24 w/w methanol to oil and 1.4% w/w NaOH to oil as alkaline catalyst to produce biodiesel at 65 degrees C. The final yield for methyl esters of fatty acids was achieved ca. 90% in 2 h. (C) 2007 Elsevier Ltd. All rights reserved.